I am not defending or condemning anyone here, but as a practical matter if you are not IT industry I am not sure that Open Systems/Platforms are appreciably better in terms of leaving you to deal with unplanned migrations.
it isn't as if FOSS projects don't lose momentum and just sorta fizzle. It isn't like they don't bogged down with management and political problems that cause them to stall or fracture, it isn't like these projects not tied to big clients writing checks don't decide to abandon features that might be critical for your use case.
Maybe you don't have to fear someone is going to suddenly jackup license costs and leave you with a drop dead migration date, but you can still be left with something that is unmaintained, and otherwise not remaining a good fit for the rest of your IT plant.
Q. what if you'd recently decided to build your storage infrastructure around Open SUSE with bcachefs?
Can you continue yes, but if you do, you'd better have experienced Linux systems people on staff that can at least build an out of tree kernel module and prepare the require boot files/archives, etc. If you only had point-click people and some vendor that did a one shot install for you, it might get expense now too.
Long term support-ability / control over software assets certainly can be a benefit of choosing FOSS but if that benefit is *real* depends a lot on your particular situation and what / how big the thing in question actually is. It is easy to say "hey the license is free I can just use it as long as I want and if it needs some old platform I can just put it on VM and isolate it!" - How often is that really true. if it is some old server that only builds against some ancient version of OpenSSL that does not support anything newer than TLS1.0, how viable is that really. Realistically you are going to have to find someone with enough skills in whatever language the implementation is to port the thing to a contemporary version of OpenSSL or GNUTLS, or give up your privacy/security, or force users into some strange cumbersome VDI scheme etc...