I suspect that they don't currently have a steady enough supply at volume to do that, though it's encouraging that you can get the batteries at all.
But this is just he tip of the service iceberg. DAG can still do full overhauls and fix M5 meters with the spare parts at his disposal. He, Sherry Krauter, and others can do full repairs/overhauls on Barnacks, M2s, M3s, M4s, etc. (I have and M2 and and M5 that DAG overhauled and one M4 Sherry did and all of them are pretty much flawless.) What are the odds that in, say, 50 years, you'll still be able to get a Leica digital replacement sensor, control electronics, or display for an M11?
And THAT is the problem. Buying Leica digital is a very big investment. These cameras already exceed any reasonable use case even the most demanding pro might have, whether we're talking about an M11, and SL, or a Q43. Heck, my 10 year old D-Lux Typ 109 covers more than enough for 90% of the shooting I do (its monochrome setting is astonishingly good). IOW, I would expect these to be good for use for a VERY long time just like their film ancestors were. But that's not going to happen because the parts supply is gonna dry up. If you don't think so, go see what it takes to fix an M8 or M9 with sensor corrosion. It's third party only and very expensive.
My Fuiji GA-645Zi cost me about $1600 when new some 25 years ago. Sending it off to fix the bad LCD cost me $600, which is - in my view - reasonable. But spending the better part of $10K for a camera I am unlikely to be able to fix at all in 25 years seems ... crazy to me.