Personally I do avoid add-ons that create special syntax in the md files so that if Obsidian ever goes shitty I’ll have an easier time migrating to whatever alternative.
If it ever comes to needing an Obsidian replacement I'd hope it can aim for compatibility with the plug-in ecosystem, at least initially. No idea how difficult a target that would be. Either way, I certainly worry about my data in Obsidian less than I worry about Evernote, OneNote, or Apple Notes, even with a couple of non-standard markdown additions.
Since it's not VC backed I'm hopeful about Obsidian building a long-term sustainable business without having to turn shitty, but who knows. I should sign up for Sync and give them some money.