I assumed you meant some kind of formal studying... otherwise it seems pretty vague; what constitutes "studying" in your opinion?
Now who is making the assumptions? An R7 would need some zooms covering wide angles FOVs at a 1.6x crop. That's a 3rd crop system.
An M7 would keep someone in the Canon ecosystem rather than leaving, which is the more important thing. I just don't buy the idea that someone unwilling to pay the cost to go FF will want to spend the money for the latest and greatest glass. An M7 with a weathersealed adapter & EF telephoto glass will work great for a reach focused shooter on a budget.
From what I've seen the real heartburn for the R7 crowd is wanting to shoot crop but feeling excluded from the RF party. What other explanation is there? Why would a flagship M7 with adapted EF glass be bad for consumers?
With the M series, I can put EF and EF-S glass. But unless Canon changes their approach on the M lenses, then as you suggested, people are going to just use their (existing) EF glass. No upsell, bar the body. At least when they had 7DII, Canon could attract buyers to the L series and upsell. M7, no such opportunity. Yes, I accept they could produce better EF-M glass, but then I think they will have to change batteries, and body size (lens plus heat) and haven't they just designed an R7? With a M7, I now have this bigger body and only teeny existing EF-M lenses which will look quite funny. Canon never developed a big range of EF-S lenses. I think they are doing the same on the EF-M.
Design an R7? Take an existing R6, change the sensor (assuming the current 32M can cope) and voila. Price it higher than the R6. It will take EF and you can upgrade to shiny better RF lenses. Use the new RF 800mm with an APS sensor? Yep. Ergonomics for the larger EF lenses? Tick on the R, not so much on the M. Re-use existing tech / design (maybe all you need to do is change the sensor) given the M6 II can do 14fps. Tick. M7 would be quite a few changes. Have your APS-C sensor (R7), and when you replace your lenses you will have lenses which work on the R FF range (another upsell). You can use legacy EF-S or EF, there is the same upsell at first, but then there's some RF glass which you can use alongside (upsell). I dont think you need to produce any RF APS lenses, just use your legacy or buy new RF. Cause that's what any 7D II user wanted if they needed good glass.
I don't think either is a clean option, but I don't see a massive change for the M range. Slighly bigger M? Sure, I can see that. If they put in IBIS and Digic X, they may have no choice. Something designed to take good sized EF glass? Personally, I don't see that.