If should was wood, house’s 'd be cheap.
Seriously, though, the only times I’ve seen stranded wires come out of the WAGOs or Weidmullers was when they were cut incorrectly, or the wrong gauge, or just shoved in. Cut the end square, cut the right amount of insulation off, don’t damage or taper the strands, do a VERY slight twist to keep the strands together, open the connector with an appropriate tool, insert the wire, release the tool, tug test.
As far as I’m concerned, the bottom line is that it’s just as easy to mess up a crimp job as a manufacturer’s recommendation job - and apparently* harder to notice on inspection that you have a problem.
* Qualified as I have done far fewer ferrule inspections than recommended inspections. In recent years, I have learned to trust PROPER crimps as much as good-flow solder joints, but I have still encountered several bad crimp jobs involving blind-end wire inserts which appeared good on inspection, but which later failed due to too little insulation being stripped, tapered ends, or nicked strands.