...... I went with RF instead of Nikon or Sony based on the gut feeling that over the next couple decades Canon would catch up.
My one solid fear is that Canon's lead in sales is so comprehensive, and so well-managed despite not having the best gear, that they may just get used to having good sales without being cutting edge.
Yes, this is the only real issue - Canon are a comparatively conservative company. They'd probably *claim* that their philosophy is to let other companies do the beta-testing, (and then only introduce things in Canon gear when they were satisfied they had the best and most reliable implementation), but the R5 overheating issues rather exploded that myth.
More likely is that Canon's sales success just leads them to sit on their laurels and appear complacent. The frustrating consequence for their customers is that we need a lot of patience as we wait for them to play catch-up, with new bodies and lenses. It's pretty much the opposite philosophy to Sony, who rush their latest technology out as fast as they can and thereby capture the early adopter techno-enthusiast market. Poor old Nikon meanwhile try very hard to produce class-leading cameras (and often succeed, ref D810, D850, Z9), but sadly have great difficulty convincing people to actually buy their products.
I'll probably stay with Canon for 2 reasons, a) the cost of switching is too prohibitive, and b) I prefer Canon ergonomics. But if I was rich enough to be able to afford to switch systems, I'd be very tempted by the Sony a1 and it's vast range of native glass. I'd rate Nikon and Canon about the same as far as lenses are concerned - Nikon have some lenses that I prefer to Canon nearest-equivalents, but likewise Canon score with others such as the RF 100-500mm. I'm very impressed by the specs and design of the Z9 (and the price!), but I don't like gripped bodies, so that kicks both the Z9 and the R3 into touch. Looks like I'll be staying with the R5 for another couple of years then.