Time and money. Analog masters don't transfer themselves. If a record label decides to transfer LP x to digital it has to devote resources to do so. Record labels have a backlog of work. Making new recordings, and moving more popular LPs that will monetize over first.
Admittedly it doesn't have to be too complicated. Transfering an old CD to digital and adding appropriate metadata could be done without even using a studio, but it can take thousands of plays before a label breaks even on a transfer.
I'd suggest you buy a CD used and rip it and consider yourself lucky. :)