to others reading this -- simplified, but, docker uses containerd to build/run images. all docker images are valid containerd images. you can run images through containerd straight off the docker hub.
Open source is fine; there's a ton of available code out there, to mix and match for whatever goals you need. Open services were never a thing, and what we're observing is that the SAAS model is eating the entire marketplace because tying services together to solve tasks is far easier (and depending on scale, more maintainable) than tying software together to solve tasks on hardware you own and operate exclusively. Owning and operating the hardware in addition to owning and operating the software that does the thing you want to do doesn't scale as flexibly as letting someone else maintain the hardware and provide service-level guarantees, for a wide variety of applications. But the software driving those services is generally closed-source.
If by "open source" you mean "Free (as in freedom) software," the ship has kind of sailed. The GNU-style four essential freedoms break down philosophically in the case of SAAS, because the underlying assumption is "It's my hardware and I should have the right to control it" and that assumption breaks down when it's not my hardware. There may be an analogous assumption for "It's my data and..." but nobody's crystallized what that looks like in the way GNU crystallized the Four Freedoms.
It's kind of a case study for future text books about how if there is a certain incentive, it will be embodied and satisfied no matter what. If the names and labels have to change, they will, but the essentials will somehow turn out to not have changed in any meaningful way in the end.
It's if anything worse now than before. At least before you were allowed to own your inscrutible black box and use it indefinitely. There was sane persistence like a chair. You buy it, and it's there for you as long as you still want it after that. maybe you don't want it any more after a while, but it doesn't go poof on it's own.
One way things are actually better now though is, now in many cases the saas outside of your control really is just a convenience you could replace with self-hosted good-enough alternatives, thanks to decades of open source software and tools building up to being quite powerful and capable today.
I think this is a case of the rising water lifting all ships. If the proprietry crowd gained more ability to abuse their consumers, everyone else has likewise gained more ability to live without them. Both things are true and I tell myself it's a net positive rather than a positive and a negative cancelling out, because more and better tools is a net positive no matter that both sides have access to use them for crossed purposes. At least it means you have more options today than you did yesterday.
For example, Al Capone had some friends, and the government violated his right to socialize with them without being surveilled for good cause.