Anecdotally, this is true for me. My Arch machine runs for months with no issues. My XPS running 10 blue screens once every several weeks, and generally has issues after running too long.
To be fair it could be due to the general buggy-ness of the TB16 Thunderbolt dock.
Yeah of course, different people will have different experiences. Mine was being never able to make wifi work, random destruction of the GUI when I plugged an external monitor, difficulty to install and configure eastern languages IME, sound issues, etc. That was a very instructive period as undergraduate in informatics, but I got tired after a while to constantly fix my system instead of getting things done. Still using it as a server OS, where it shines.
I've jumped from Debian 7 to Debian 9 without issue, and the Gnome Software Center makes installing apps a point and click process (reminds me of Click N Run from Linspire...).
There are notable fit and finish issues with other distros, but from what I've seen the Debian package maintainers consistently make decisions to protect the package archive from breakage, whether that be holding back a FreeCiv point release over a buggy UI element, or stripping out non-free parts of Chromium that upstream bundles.
It depends what distribution you're running (and what time we're talking about, ten years ago was a different situation), but if you're on a mainstream long-term release like Ubuntu, Fedora, Suse and so on, it's pretty smooth nowadays, on average at least.
Yes, there's still the 1-2% of roughness around the edges, but as OP pointed out, on linux you can actually fix stuff. It is definitely not an "april fools" worthy statement. Linux is really stable these days.
To be fair it could be due to the general buggy-ness of the TB16 Thunderbolt dock.