Take a look at these bikes. They are your basic rental bikes that exist both here and all over Europe. They were in western Germany and are quite standard and functional.

I rented these for several days and were quite basic and adequate. On the other hand, whilst in Bavaria I went for a shop-based rental and got something that though more advanced, did not really have as much comfort.
It was while I was outside the shop, that I noticed MANY second-hand bikes on sale; at surprisingly high prices in my opinion!
Prices from left to right €549, €449 and €239!
I can only put this down to the German mentality of not wasting perfectly good bikes and / or their emphasis on useable quality. All of these will easily stand the test of time, and no doubt can endure the rigours of city use.
CB