A town is full of carpenters that make furniture. They understand the variety and quality of various woods, from oak to ash to ebony. These carpenters can easily discern the quality difference between one wood and another.

Over time, the carpenters die out and are replaced by people that can’t tell the difference. To them, an IKEA table made of compressed wood is the same as a handmade table made of high-quality wood. Ergo they have no ability to discern the quality difference and think they are all the same: wooden tables.

In terms of language: if language is merely becoming more simple and following its own rules less, then that seems like an analogous situation. It’s not simply becoming something else, it’s becoming dumber, less complex, less adherent to the rules that previously defined quality. It’s not doing this as a consequence of pursuing new levels of quality, but merely because the previous ones are decaying. I don’t think comparing two languages like French and English together is quite the same thing.