I take it these are the bathrooms that are failing marc ?
Bad floors, bad prep bad walls bad prep all in all a crap job.
I can show you hundreds of shower rooms , mine included , which is used 3/4 times a day for nigh on ten years, no leaks apart from the crap shower screen.
I can show you showers ive never tanked which are fine, mine included , i can show you pebbledashing/rendering which i used loads of pva on which are solid after 30 years , no cracks no blow offs, i can show you women i have slept with who .... Hang on, off topic
All im saying is if its prepped right and the job is done right some things are just over kill
Ps you can say i told you so all you want, mine aint failed , ever my man, and ive filled ever corner ive ever tiled