I live in a HA property. My son and I moved here because we needed housing desperately after a family crisis. Our social landlord is a large HA and as well as providing properties and maintaining them, they offer training courses, tenant's voice panels, social events for their elderly and disabled tenants and all tenants receive a newsletter showing how the HA performs against a number of measures. They are, in my opinion, a good social landlord.
Even if I could buy this house, I would not, because all I would do is make one less property available for people who may be in as desperate need as I was a few years ago.
Furthermore, we live on a terrace of perhaps ten houses. It is possible that three or four people could (perhaps) buy their homes, if the right to buy scheme came about (there is a right to buy scheme for HA properties already in existence, but that is beside the point). That would mean, three or four homes would have their doors painted a different colour to the rest, would grow little conservatories and would put lattice work around their windows to mark them out as 'bought' properties (we saw this happen in the eighties). Yet these bought properties would still be part of a terrace which is largely social housing, so little name plates will be added instead of numbers and larger cars would be parked on the paved front garden, in an effort to create even more distinction between 'homeowner' and 'HA tenant'.
Of course, the bought house could be a legacy for the children. Yet, it is more likely to be something that is sold to pay for care fees in old age.
So, I agree OP, Boris's proposal is nothing more than a vote grabber. I think Margaret Thatcher must have left him her book of tricks.