Service is one thing, bringing out new and improved lenses or bodies another. For over two decades the path was clear and one could happliy buy into the system, assured that there is one system. That was kind of a guarantee, which made this a very safe home.
But that's not actually true - we had no guarantees Canon wouldn't bring out a new system at any point in the past few years, indeed plenty of people were predicting a new FF system, with no consensus on whether it would be EF or something new. Now we have a better understanding of their plans than we did before, because the new mount is out there. You can *still* buy into the system - as others have said here numerous times, EF lenses work fine on RF bodies. And service will continue on EF lenses for years to come - I don't see that being impacted by the introduction of RF at all. All lenses' service lifetimes are finite.
It will drop as it always has when a new version of a lens is released, but it never falls off a cliff. Look at e.g. the relative secondhand prices of each version of Canon supertelephoto lenses - the older ones are still expensive.
Another choice I am confronted now is to stay with canon (not likely with the EOS R), or switch to another system all together, since buying another body is a given fact someday. Canon may bring something to the table, but judging from the latest releases, I am not convinced that they will or are able to. EOS R is not for me, too many things that annoyed me (ergonomics, not working features) during my tests with it. If they would have done it differently, I would not question this at all.
I think you're being premature. Unless you have some compelling reason to make a change now, why is it urgent? Your current gear still performs as it did. Judging a line based on its first iteration is frankly silly - look at how the M line has matured, and indeed compare the current Sony bodies with their earlier versions.
You'll see it soon enough.... but I will give you a hint ... Ap??? !!!
To put it mildly, WHAT OTHER COMPANY could have afforded to buy me a Bell 429 ???
...and I actually GOT PERMISSION to leak that word noted above in that particular manner, which is NOT a normal thing for them to do ... which shows you JUST HOW IMPORTANT this new type of CODEC and advanced CMOS SENSOR technology really is !!!! --- AND....there is a heck of a LOT MORE COMING DOWN THE PIPELINE with this technology!!!
In September, there will be a DELUGE of NEW products to make consumers drool! AND YES! I got permission to say this too!
Most interesting lens for ME. A compact IS-less f/2.0 100mm 1:1 (extending if necessary) including focus limiter would do the job as universal short tele lens. Combined with a 50mm equiv on M50 it would be THE small high quality walkaround set for me.