"Just not immediately" is a big fucking deal for people in Amsterdam who use their bicycles as their primary means of transportation. Imagine you lived in Phoenix right now and the same thing happened with your car. You dropped off your Rivian or Lucid for repairs and -- surprise! -- they were actually on the brink of bankruptcy, so now the only way for you to get to work, pick up kids, etc. is to try walking, biking, or busing for miles in 110F+ degree heat until the courts figure out how to get your vehicle back to you.
If I depended on my bike for transportation -- as is the case for many people in Amsterdam -- then holding onto my bike for more than a few days for a repair is effective theft of my primary means of transportation. If the mechanic tells me they can swap out a part in a couple of days and needs to keep the bike for that, no big deal. The milk in my fridge won't spoil in that time, and I can WFH for a couple of days. Maybe take a while longer to get to and from daycare by walking and busing.
But if my bike becomes unavailable for much longer than that, at that point I would be forced to treat it exactly like a theft and purchase a replacement so I can travel the way I need to again. I still need to buy groceries and get to the office in a reasonable amount of time, and I don't have weeks or months to wait until the courts/lawyers can finally figure out WTF is going on with the property locked in the stores. Sure, chances are I'll eventually get my means of transportation back, but by then it will be too late, since I will have been forced to replace it by then.
It's de facto theft.