My DMum who is 96 is wartime generation.
Allowing for wartime roles (such as being a Bevan Boy or a land girl or a nurse) which started at 14 or 15,, I think it means those over about age 93.
The Royal Hospital Chelsea said during its Founders Day celebrations this year (which had a bit of a 80th anniversary theme) that they had 13 pensioners who had seen active service during WW2, one of whom had been at DDay.
So in the strictest sense, there aren't very many left.
But I think that if you mean it in a slightly more general sense, of the over 90s, who are frail, and who need extra warmth, or just extra care in the winter months when getting out and about outdoors is that bit more treacherous, and who are simply not in a position to boost their income; then yes it's a pool of people who are vulnerable.
Most pensioners are not rich. Those who perhaps were in their earlier retirement may well have seen their entire income/savings taken by care costs by the time they are 90.
I'd have changed the eligibility to all those on pensions credit, plus all the super-elderly (maybe as low as 80+, but certainly 90+)