I have some thoughts on this because I also reached this conclusion after reading the "specs" we're all taking as fact.
1.) There isn't a single lens on the EF-M mount I would want to adapt on a full-frame sensor and then crop in. It's no secret that the 22mm is a great little lens, but beyond that, only the 11-22mm is really anything special. I have the M50 for size and convenience. It's a somewhat pocketable 80D and it's what I use it as exclusively. I pack a full roller bag when I travel for work and can slip the M50 with the 22mm almost anywhere. The M lineup of lenses...or lack there of, have all shared a focus on size over performance. It's honestly what I like about it. Sure, faster lenses would be nice, but with more light comes more heft. It's fine if they wish to offer larger, faster lenses...but it doesn't appear that Canon is considering that with zooms any time soon.
2.) If these rumors hold true, Canon will now be selling lenses for four different camera mounts - EF-S, EF-M, EF, and RF. The only true discrepancy in this lineup is that the two mirrorless camera mounts won't play together...I'm sure Canon has looked at its lens sales and understands it's not really missing out on very many cross platform support. As mentioned above, Canon full-frame was never able to work with EF-S lenses. But, you have now lost the upgrade path of buying a crop sensor body and investing in full-frame lenses to upgrade over time. You can no longer do this in the mirrorless ecosystem
What does this mean for the future of the EOS-M mount? Like others have said, I really hope they maintain a priority of keeping the M system as compact as possible. God knows that the RF 28-70 and 50mm f/1.2 won't be. If you want a light, consumer/prosumer camera to take on vacation, shoot video or vlog with, the EOS-M series is your ticket. If you're looking for a professional mirrorless system, the RF cameras is your choice.
I admit, this creates concerns for the future of the M-mount. But I'm extremely happy they didn't try to force the mount to work with full-frame and make sacrifices in capabilities, performance and the future overall.