That was my conclusion as well, everything was simply insanely cheap then compared to today. A car today cost much more than 3 months salary, and to rent such an apartment would be basically impossible.
The rent was 12% of his income only. Which means a bachelor with a middle class job could easily rent an apartment with 4 bedrooms and 2 sitting rooms. LOL
Everything was much much cheaper. Except exotic food groceries.
Most things were cheaper for the (then rather small) upper-middle-class, yes. For others, not so much. A lot more people had to choose between starving and freezing in 1919 London than in 2021 London.
I wonder how finance worked. Today a car might cost 3 months of salary, but I can get a loan to pay it off over 6 years. If I had to buy a new car without a loan I couldn't afford it because I don't normally keep that much savings. (Ignoring retirement savings which technically I could tap into)
In Romania something like this happened with house prices. I bought my first flat just as credit was becoming available for the general population - it costed me 27k USD; at that time, it was customary that you'd pay in full for an apartment, people were actually looking suspicious at you for involving the bank!
One colleague of mine wanted to keep saving and pay for an apartment in full; he didn't manage to, even though he was more senior (read: earned more money; also he lived alone, could save more than I could). What happened was that prices increased faster than his savings rate - effectively by waiting he lost money, and eventually gave up and took a credit. Now... there were multiple factors for the increases in the housing market, credit being available was not the only one, but I do believe it was one of the main drivers.
The rent was 12% of his income only. Which means a bachelor with a middle class job could easily rent an apartment with 4 bedrooms and 2 sitting rooms. LOL
Everything was much much cheaper. Except exotic food groceries.