Absolutely PhD’s are required.
lecturing and university education isn’t just about the content and passing exams.
it’s about methodology, about pushing forward new ideas, inspiring minds.
most universities aren’t churning out a’level students with 3 years more learning. graduates should be able to think critically, assess others work, use it to drive their own research. It’s not simply repeating what others have done, you need to be able to read a paper and think “oh, I wonder if anyone has tried this to see if this happens, or shown that this related theory is true” - then think of how you would do that, how you would structure your process/experiments/reading, then gather the information, the evidence and interpret it.
if you haven’t done that in an academic setting- ie a PhD, it will be almost impossible to teach.
decent uni’s want to produce thinkers, not memorisers. If uni’s employ people without, simply to teach, then that is not university level education.
again, I am out of date since I did my PhD, but the vast majority were funded. The only people I knew who “paid” to do a PhD were international students. Generally, if you weren’t funded it was pointless doing the research. Granted it wasn’t much, but was enough to live on reasonably comfortably.