I’ve lived and worked in several large european cities, commuting in most of them by bicyle, and the most I ever spent on a commuting bicyle was €250 and generally it was more like €100 because I usually bought them used.
Finding a cheap bicycle was definitelly easier in The Netherlands, but I also got some nice cheap second-hand ones in London and Berlin.
Absolutelly, those things get stollen (which is why you get a lock, but even then, all it takes is a mistake and it’s likelly you’ll never see that bicycle again), which is why you don’t pony up for a brand new carbon fibre bicycle for commuting unless you’re planning on making a big involuntary charitable donation to a random bicycle thief.
I’m not even against you advice to walk - were I am it’s quite dangerous to cycle (here in Portugal drivers are some of the worst in Europe) plus I live in a small city nowadays, so unlike most people here I refuse to buy a car and mainly walk - it’s just that human-powered cycling is a more natural alternative to E-Bikes than walking in places were drivers aren’t quite as bad.