The erosion of services has lots of causes.
Overall there has been a secular decline in gas turbine starts and hours industry wide. Fewer spare parts are needed for the newer turbines. Strike 1.
The newer turbines are designed to last much longer without needing replacement parts. Strike 2.
Third party vendors are moving in on the market to supply the older GT's sold 10-20 years ago, the bubble years. Strike 3.
GE thought that AMW with it's ability to quickly print a part would be a savior but it is NOT the low cost option and has turned out to be a niche source of parts. Yes, there is less of a need to keep an inventory of parts on the shelf but that's a cost thing and not a revenue thing. AMW doesn't make customers order replacement parts nor increase new unit market share.
What's GE's market share in Wind?
So, about your second paragraph,
GE is desperate to get Digital and Predix going but they ran into a real problem... people vs. parts vs. intellectual property. The people needed to do it leave and when they leave then they take their know-how with them. There is nothing to stop them completely reinventing their methods at another place. GE approached digital like it approached past products, i.e. spend money, make a product, sit on its a-- and rake in the bucks. In digital, unless you constantly innovate, all you're doing is training your future competitor, a future third party vendor. There is no "revenue stream". Last in order to constantly innovate the lowest level people have to be put in charge of their own work and GE management finds that idea too far outside its comfort zone.
GE power's management will have to be replaced one way or another. They are too stuck in their ways. It cannot be done from the inside out because GE power's management can't pick their replacement. They don't recognize their own faults. Whatever they pick would only look like themselves. It will have to be done from the outside in and that's been painful for everyone.