Or one could buy any of the existing pre-built splits. Which might be more expensive, but it does not involve something one very explicitly said they don’t want to do.
I’d rather spend twice as much on a well built keyboard with warranty than trying to solder one together myself and botch it up, and then it suddenly costs more than if I just bought a pre-built one.
It’s about 5 times longer than previous releases were maintained for, and is an experiment. If there’s a need for a longer term support branch, there will be one. It’s pointless to start maintaining an 5+ year branch with 0 users and a handful of volunteers, none of whom are paid for doing the maintenance.
So yes, in that context, 15 months is long.