While I agree with this premise, I believe we ought to exercise a sense of proportion about the scale of the risk. The same things are true for written rather than spoken language, about LTR or RTL, about type vs pen and paper, about PC vs mobile. The OSs vary and Apple, and to an extent MS, love the idea of raising the wall around their gardens. Languages vary in their linguistic structures and the vocabulary. The programs many users switch from have both a locked in format as well as developing conditioned reflexes in workflow.
With Obsidian, the core program preserves all data in the open - though readability will depend on what is typed and the knowledge of the reader. Plugins, of course, are free to squirrel almost anything inside a database, but the way they work is, initially at least, visible to the developers and the community.
afaics most users want to do everything within this one program if they can. That does imply greater friction if switching to something else, but it’s a free choice and hs its own advantages as well as disadvantages.
I prefer using multiple tools which automatically reduces lock-in risk. I use Obsidian much less than I would if it worked natively with txt as well as md. But the multiple tool approach has its own costs, not least the cognitive load of maintaining familiarity with some quite different ways of working.
I do agree that understanding the risks, advantages and disadvantages, and compromises implicit in any choice should be important for many users. But for others it’s just something they use for some tasks, for a limited period in their lives and worrying about long-term effects and risks is irrelevant.