Some people have lots of friends, some don't. We're all different.
But here's a thought, CyclingSenior. Perhaps you make such an effort to make people feel welcome and enjoy themselves that others feel they can't match your successful evenings..
Also your circle may have got smaller simply because friends own families have increased with more time being spent with gc etc.
Perhaps you are assertive, but do you want to change to attract friends or pretend to be different. Is it that important? Or should you perhaps try for some new friends. I think you might like U3A. I am a member and its a good way to meet people whilst taking part in a shared interest.
I like the idea of being able to say I have lots of friends and sometimes I feel that I am lacking in not having a big social circle, but if I'm honest with myself I wouldn't have the energy or desire to invest in it.
Sometimes you need to actually sit down and discuss with yourself what kind of friendships you really want. Not what you think you should have or want.
I have health problems too which affect energy, and probably many of us are like that as we get older.
My best friend died less than two years ago. We had known each other over twenty years. We met at church and just clicked, we were just on the same wavelength. I made another friend three years ago the same way. Just instantly bonded. Sadly she had to move away last year.
If I'm meant to have another friendship like this, it will happen in its own time.
I have another close friend, but she is more like a sister than a chosen friend. She rarely comes to me but prefers me to visit her, if we aren't going out. I'm actually trying to change that (not very successfully)
Like others I am happy at my art or other things I enjoy doing, meeting like-minded people and enjoying a chat/occasional coffee, without too much being expected.
I think many people have less friends as they get older and other groups may look like they're having lots of fun (just as facebookers look like life is wonderful). and some may go home thinking, goodness what boring chat (I'm thinking my daughter would say this)
And perhaps you are self-conscious about your accent which you shouldn't be. Why is one accent more acceptable than another? If folk don't like your accent then they aren't worth your attention.
Don't think about it so much is my advice. Just get out and do stuff and enjoy.