Christmas entertaining, how do we cope with ever increasing family numbers?

It sounds very much that your DH doesn’t want to give it all up just yet, but definitely needs to make it a less formal day.
I think the buffet idea sounds good, but I’d get him (after all it’s his family) to put the word out in advance, so those who don’t enjoy buffets can make alternative arrangements. DH can still be in charge of the drinks, but he’ll be able to join in the day and not be stuck in the kitchen slaving over a hot stove.

I’m sure I’ve asked before on here how many people are actually doing exactly what they want at Christmas, and the answer was very few.
Why not ask everybody? You may be surprised, and they may prefer a Christmas Eve buffet or Boxing Day turkey sandwiches with Prosecco!
I’m going to the sun.

Semiruralgirl: ‘We did ask everyone to contribute ahead which they did except for the large family with the extra friends and relatives. They pleaded poverty and said they couldn’t afford to contribute………….’
Gordon Bennet! What about the money they are saving on not buying everything for a Christmas day at home? Perhaps they wouldn’t invite quite so many if they were doing the work and paying for it all themselves. You and your husband are extremely tolerant.

It sounds horribly grabby and one-sided, I definitely wouldn’t be happy, let alone be able to afford it.
I suggest that DH asks his DCs to host for the next few years because he needs a break. If DH won’t then I’d take myself out for Christmas (I’m bah humbug anyway at the excessive cost of Christmas etc, sorry!)

We are the same, and I was the. One who “did” it. But last year before Christmas I was proper poorly with covid and then flu and so my son took it on. We had a whale of a time and everyone voted to go there again, which seems a bit unfair, so my daughter has offered this year - at the moment I’m waiting for instructions😄.

I think you may find it difficult to book a room and meal for such large numbers now, so perhaps grit your teeth for one last time, one last bash; and use the Christmas feast to announce that this is your last year as hosts, and let's discuss who is going to host/arrange next year?
Smile sweetly and do not be swayed by but 'you always do it; Christmas won't be Christmas without coming here etc, etc.

I did know one family with four adult children and grandchildren who all descended on their parents every Christmas until one year a brave daughter, hoping not to upset her mother, said: 'we would love it if you all came to us next year and we don't want to upset you mum ' whereupon mum said: 'I have been hoping for years someone else would do it, it's too much for us now; we would love to come!' and everyone in the family took it in turns after that.
Relief all round.

If everyone is local why not try a “ gourmet gallop”?
Drinks and canapés at one house, starter another etc etc?

I should say about the several days bit, that that is then spread around three households, including ours.

We always cater for that type of number.
For several days.

Christmas Day alternates between us and another family.
Our house has room around tables[have trestle table as well as main table].
Other family struggles with room.
The whole thing is now spread around 3 downstairs rooms.
Even been known to put kids in the hall!

Some of us are part of a much bigger family group.
In that one, we hire a hall.
Christmas season but not the day itself.
And everyone brings something.
No one tells others what to bring.
We bring what we want to bring.
Doesnt matter what it is.
Works well.
If there are too many crisps, or not enough salad or something, well no matter. It is only one or two meals.
And if your food is not eaten you take it home again.
The hall has a kitchen available.

It sounds like your DH and you aren't quite ready to give it up if you look at what you want to have control over. And that's ok, but it then means you're stuck in the same situation. Perhaps the grown up children don't think of how difficult it has become because dad is dad. If you see what I mean. The freeloaders will continue to freeload unless you categorically tell them you aren't paying.
FL "It's too expensive for us."
Y "that's a pity. We hope to see you at some point over Christmas.
And don't back down!

There is absolutely no way I could tolerate that arrangement!
Maybe you could book a restaurant where everyone has to pay a deposit? Anyone who turns up and cant pay for their meal can do the washing up or get arrested haha xxx

Buffet style bring and share? Maybe you provide the turkey and, say a ham, which can be cooked the day before, and sliced up on the day, and the wine as you said DH likes to provide that, but ask certain groups to bring other specific items such as veg, (prepped) potatoes, (prepped) puddings, (made and ready to go), trimmings (prepped), so it doesn’t all fall on you.

However, it really sounds as if it’s becoming a big issue for you, and deep down you can’t cope with so many people there on the same day, so you really do need to sit down with DH, now, whilst there’s still time for family to make other arrangements, and say to him that it’s all becoming too much and too expensive.

Instead of Christmas Day being the focus, instead maybe opt for a buffet on Boxing Day if your DH still insists on inviting everyone, but a bring and share buffet?

Either you or your DH need to have a conversation with his adult children. Be frank - it's too much for you to do, time for a change. What do they suggest / want?

Maybe everybody secretly feels the same and will look forward to doing things differently.

Good heavens, I couldn't cope with all that! My suggestion would be to make a booking somewhere then as there are so many people treat it like a work do. Everyone sends you their choice from the menu and their money, then you pay the venue. Or better still, tell them the place, date and the time and get them to book and pay for their own group.

If you want to pay for other family groups that's your choice but they do sound like freeloaders if they expect you to pay for them.

You just say you're getting on a bit now, cannot do it all much as you'd love to.

You ask whose house you will, all be congregating at this year - they're adults now and can step up to take their turns!