Same thing happened when the analog cell system was shut down nation-wide. Lots of home alarm systems suddenly had no way to contact the monitoring company that people were paying $24.99 a month for.
I've got a similar problem with the navigation system in my Lexus - the last maps for the DVD-based system were published in 2015, and there won't be any more updates. I now know what it's like past the end of the sidewalk.[0]
For a vehicle as old as mine, technological obsolescence isn't really a concern - it will still start & run, the windows will go up & down, and I still have a real metal key. Will there be lawsuits around electronic modules not being available for newer cars? Probably. But I also expect that there will be small businesses that specialize in repairing these modules. There's one that repairs the Mark Levinson amplifiers [1] used in Lexus vehicles. $1500 + labor for a new one from the dealer, vs. $400 for a repaired one from them is pretty attractive.
[0] The underappreciated Shel Silverstein
[1] I believe most of the repairs are just replacing dead output transistors. Easy thru-hole soldering.