I bought my home at 21 with my then partner 13yrs ago.
To do this I worked very hard, had NO luxuries (by this I mean no new clothing, no car, no eating out, no cinema trips etc - we basically didn't have a life). I had no handouts from parents as my family have always struggled for money.
I do think that a lot of people these days aren't a poor as they say they are. If you can afford to drink/smoke/eat out/have little treats/spend £5 a day at Starbucks, then you could be saving that money towards a deposit which is far more important in my opinion. It's about budgeting and scraping every last penny into a savings pot. We managed to sort out a 20% deposit within 4yrs despite being on low incomes.
I understand that London prices are higher, but generally, so are the wages. Also, once on the ladder your prices rise higher. I've managed to put only £10k on my house in 13yrs - which leaves me struggling to buy a larger/better property.
It’s not just about London though! Your experience is not universal.
I went to uni in the midlands and then moved back to the south coast where my family were. The main reason I moved back was because there was one company there in the industry in which I wanted to work, my only other options were London or Bath, which were as expensive or more expensive. London would have come with higher wages, but also higher rents.
I’d put myself through uni, my course didn’t allow me to work during term time but I worked every hour going in the holidays, and still left with several grand on an overdraft. Took me 6 months after graduating to find a decent job, until then I worked minimum wage which barely covered my rent in a hideous flat share. I skipped dinner most nights.
When I did get a job with the company I was hoping to work for, my starting salary was £11k. Moved to a slightly nicer flat share after one of my flat mates was mugged walking back to our flat.
I’ve never owned a car in my life, rarely buy clothes, have always been frugal - took me several years to pay off my debts, let alone save anything.
Company went bust and had to move to London. Rented a tiny 1 bed council flat - it was cheap, but turned to out to be an illegal sublet so had to move. Was on a decent wage for the first time ever and was achaily able to save some. Then my health deteriorated and I ended up having to give up my career and move back to my home town at 29. I then tried to be self employed and make some money rather than making nothing because I was too unwell to hold down a regular job.
DH and I only own a house because my mum died and I inherited part of her house. My mum had never been in a position to help us financially in any way, but her life insurance paid off her mortgage in full. Without that, we’d still be renting and struggling to save (our rent was nearly double our current mortgage payment but then we had a 40% deposit).
The fact that you could buy at 21 would have a lot to do with your personal circumstances, the fact you didn’t have a single income for mortgage calculations, the fact that you must have bought somewhere where the properties are an attainable multiple of average joint income. At 21, a one bed flat in the town where I worked was 10x my salary at least. Saving a deposit wasn’t even the biggest hurdle - it was borrowing enough to buy in the first place.