It's only partly true,
many people indeed have a Minitel at home, because it was free to have one (like it was free to have a landline phone). You only had to pay for the usage. And there was great services not yet available on WWW : find the train timetable, find the phone number of someone, chat with a (fake) sexy girl...
As for the PC penetration, there was many, but most of them where not ready for network usage : Commodore, Amstrad, Amiga, Thomson and first generation IBM-PC with MS-DOS. Only the last Amiga, Macintosh and IBM compatibles had the software to use a modem (Thomson had included a Minitel as dual bot in some of their computer instead).
There was no need for internet or to change the computer when WordPerfect, Multiplan and games still work perfectly. At the time, the pricey computer than you bought in the 80's was still good enough in the 90's...
I think than what had incite people to get a computer with modem is not WWW but email (with was not a Minitel feature). The real thing than Minitel hindred in France are Bulletin Board Systems. They where never really a thing in France.
For the curious, there are still a few unofficial Minitel services available : https://fr.wikipedia.org/wiki/Micro-serveur_Minitel All you need is a Raspberry Pi and a modified Minitel...