I do not think anyone but Lionel can speak to what they "intend". Plus what is intended at one moment can change in another. Especially where customer expectation come into play. Regardless, I think your analogy is still wrong. Regardless of how fast technology can refresh in any industry does not mean it refreshes that fast in others.
Model train industry has always attempted to be backward compatible as trains have not been treated as throw away toys. Despite its Age, Legacy and ProtoSounds did get technology refreshes. Lionel totally redesigned and implemented new Legacy boards retaining the standard of communication. The system still evolves with new software, and the whole premium line evolves around it.
The fact that LC+ communication is newer, better, is inconsequential at this point.
Despite what you want in a TV entertainment set doesn't mean everyone wants it your way. So DVD are still a main stream item, and if your a want it now, usually DVD are the next release after the movie comes out, not wifi streaming.
Lastly, despite the crowd that wants it simple, there are a lot of tech stuffed in that LC+ engine in a single integrated board.
This really is not the Large Layout operators with Large scale Legacy engines wanting small O-27 engine to run off legacy. It is a segment of the market that has TMCC or maybe Legacy, but on a smaller scale and smaller budget that would like to be able to run LC+ off their TMCC/Legacy Remote.
So Lionel need to assess the market, and adjust their intent if they thing there is a market and a profitable one. G