the article is a call to get you comfortable picking/using BSD, and from my point of view it's reasonable to advertise its maturity.
I suspect you are correct because newest and greatest typically solve a problem, and that's the focus for the devs. the more senior devs I know take an "optimistic but cautious" approach, while less experienced devs/non-devs typically just see an answer to their particular problem and want to use it, as defending the use and the few broken instances is typically easier than solving the issue without the latest and greatest. and I can get that easily
admins probably like old and trusted because boring is exciting for them; for a few of the systems I admin, it's great to have a few on debian/bsd where they've proven that I don't need to babysit these systems; they're never fully out of the equation when troubleshooting, but it comes up rarely, and if worst comes to worst, a reboot on these systems is typically so fast and non-disruptive that it's an easy decision, which often helps and then the issue never returns. sure it's not good that I had to reboot, but a down time of 10 seconds while I boot and it never comes up again is appealing.
Meanwhile qt6 is under active use and development, so I'm much more likely to find help and bug fixes, and developer interest. And it's less likely to say, stop building because cmake deprecated some ancient feature, or uses some ancient and now incompatible library.