YABU just from a factual perspective to say "the country" - there are still lots of places in the UK where it's perfectly do-able to buy a house. I'm 32 and the vast majority of people I know from school, work, friends, and uni have by now managed to buy, some are on their second or third houses. Real mix of jobs too, not all high fliers. My sister (admin on £17k) and partner (plumber on apprentice wages) bought last year aged 26 without parental help and many of their friends had already done the same. We don't even live in a particularly cheap area, there are places 30 minutes away much cheaper again.
So it is doable in "this country", it's just the prices in certainly the south east, and various other pockets around the UK are insane.
Again, only pointing this out as a fact, rather than agreeing with the ethos of it, I don't think it's fair that people born in expensive parts of the country would have to move a good distance away to get on the ladder, or that it's a good thing if they then move and push up prices in cheaper areas.
I refuse to believe that 98% of keyworkers now can't afford to buy a house and would like to know where you got that from? Firstly because "key workers" include people like surgeons, senior doctors, head teachers, senior police and council staff, etc, all of whom are paid significantly more than the average wage. Secondly because, as I've said, there are still huge areas of the UK that are affordable, where your "normal" teachers/PCs/nurses etc on c.30k could easily buy a house with a 10% deposit. Of course a cleaner on minimum wage might not be able to buy in London but those circumstances don't make up 98% of keyworkers!