Surely if it's on the roadmap then better to address it now and potentially avoid it rather than dig in deeper until sunk-cost fallacy suggests there's no way back?

Sunk costs?

How are there greater sunk costs related to switching distros later instead of now if Ubuntu starts actually misbehaving in a significant way?

I grant you, if you haven't picked a distro yet and this whole thing bothers you, by all means, pick something else! That's the beauty of the Linux world!

But if you're already in the ecosystem (and I have to assume most people complaining are... Otherwise why waste energy complaining about the actions of a company that doesn't affect you) I don't see how the sunk costs fallacy applies here.

It's sadly not as easy as you make it sound. I was recommended to use Ubuntu for my work laptop because the IT team couldn't guarantee support if you used another distro. I know my way around and particularly love Manjaro (and worked with Debian and SUSE and Mint) but the company uses proprietary VPN and a spy/monitoring agent and I wasn't sure I'll be able to make those work on a non-Ubuntu machine.

So yes, there could be huge sunk costs. After fighting with this work laptop for a full work day to get every single step of the onboarding completed, I am not looking forward to doing it again -- even less so if the proprietary and mandatory programs that I have to install can't be guaranteed to work on anything outside Ubuntu.