multi layer boards are usually not an issue for an expirience tech that would know where to go to next. Its just repairing the circuit when something self destructs them in between layers.
I like tube hybrid amps the other way: Tube preamp and solid state output. I think it’s the best of both worlds.
More than one US brand will no longer sell their boards (or other parts for that matter) to third party shops. Part of this is to protect IP from the current climate that encourages IP theft and counterfeiting, but part of it is to maintain factory control of QC.
FWIW, there aren’t a lot of “experienced techs” out there offering repair services on current high end audio products. McIntosh is the best at service center support. ARC has a few approved alternatives to a return trip to the factory. With Levinson, Krell, Burmester, Conrad Johnson and several others, a local privateer is unlikely to get factory part or schematic support.
Point to point allows the clever local guy to “repair, and even upgrade” a piece of broken gear without a schemstic or factory part support. What is going on is a lot clearer to the naked eye.
Guitar amp techs who are willing to troubleshoot far prefer point to point. Guitar amps don’t have to achieve perfect amplification. Distortion is sought after and characterizes the sound of the amp. Audiophile amps are trying to be perfect and consistent. Point to point makes it more difficult to achieve the desired consistency.
It’s not important. People like Prima Luna, going so far as to see them as an audio sandbox for tube rolling. Point to point works well in this marketing model.