Why would you expect to be able to buy a similar house to your dad, what, 50/60 years later? They're already owned by your dad and everyone else's dad. I'm guessing we're talking a 2/3 bed house as well, not a flat.
I've no idea where you live but you only need a £10,000 deposit with the HTB scheme to buy a £200,000 property. Probably even enough to get a flat in some parts of London. If that took you 9 years then that's saving less than £100 a month whilst staying at home which is very low. You'd normally expect to pay anywhere from £250-500 renting, which could be saved. If you (plural, not you personally) were able to save £500 a month living at home then it'd only take 10 months to save the same deposit. And with the new LISA's or whatever they're called, the bonus would likely cover stamp duty and legal fees too.
A couple of issues there.
Your argument is basically that you shouldn’t expect to have as large a properly as your parents at the same time of life. So where does that end? Your parents get a 3 bedroom house, you have a 2 bedroom flat, your kids... share a bedsit with others?
Should we be telling the generation born in 20 years that they shouldn’t expect to live in the same type/size of house as “we” do now?
Secondly, even when discounting the first point, it’s all very well arguing that people shouldn’t expect/hope to own the same kind of property their parents owned (in this case a 3 bed house), and should be happy with a 2 bed flat, but how is that going to help if they want to have a couple of kids?
Unfortunately it’s becoming increasingly apparent the baby boomers and to an extent some/most of generation X had it perhaps the best any generation has and will (at least in the relatively near future) have with housing. Before them owning a house was only a dream for most. Small terraced houses/cottages were the norm, as were sharing rooms with siblings. Post WW2, perhaps because of the massive building boom after the war, housing became much more affordable, owning a house with multiple bedrooms was a possibility for most.
It’s becoming increasingly apparent that that’s becoming less the case now, with house prices being multiples more than average wages (10-12x* for the average house in the UK, out of reach of even a couple working full time). Perhaps the boom of homeownership is over and we’re heading back to the pre war period?
*to put it into perspective again, average house price in 1980 was £24k and average wage was around £6k, so a 4x multiplier.