Furniture is big and unless a charity knows it will sell they would have to pay to dispose of it. It's not always that young people are fussy, my children have had second hand stuff, but with smaller houses, will it fit in. Made up furniture doesn't fit I to a car as would a flat pack, if someone had to hire a man with a van they will set cost of that against cost of flat pack, if flat pack is not much different which would fit them.
Yes people get made homeless and need stuff and usually when a plea comes people do offer. But if you are giving away a sofa in Inverness and the poor woman needing stuff now is in Exeter that's not much good.
Freecycle is often a good way or local Facebook groups, if charity shops can't take them, or local community groups who might know of someone in need.
People are saying ercol doesn't go but you do see them being sold. On antiques programmes, so may be worth trying antique shops or auction houses