With all due respect mate I dont think you know what your talking about here...
Correct that I don't know the boards at all. But I do know all about is designing a system and sparing it so that it can be operated for 20+ years. I created examples of what could go wrong, when the supplier decides to change configuration. (What if they go broke due to the increasing completion in this market?).
Consider it from a repairer/restorers perspective. A workshop will need to keep a huge spares catalog, with a pinball manufacture constantly updating the architecture. The board would become as difficult to source as a playfield game specific part. ...Ok not a bad as that as these boards are much more wide spread around the world, also within some iterations of updates of the board there should be back compatibiltiy.
...Think of what it would mean if USB gets replaced with Firewire and then Firewire gets replaced with Thunderbolt. So far neither of these two interface standards have managed to impact USB, but you don't now what is to come. Even more simply, what if the Ethernet port you rely on is removed as a cost saving measure under the assumption that everyone now uses USB.
If you have a MMR on order, you really should buy a spare board. The good news is that they are only about $50, which is of course why they were selected in the first place.
