Did any other manufacturers build their own version? It seems like the right long term idea but the lack of other players seems to indicate there's some underlying issue that isn't solved yet.
GAF did. There are two issues: 1) too expensive 2) not modular. I like that I can separate my solar decision from my roof decision. Panels make that possible.
I did consider but there are 2 issues. 1. Efficiency. Not all roof parts can be exposed to sun. You overpay 2. You need to time it with roof change
There are a few companies, I remember Invisible Solar which produces modules which look like traditional clay tiles.
The market pitch is different tho, they are aimed at providing less effective solar for places where you have a hard need to keep the old look, old churches, monumental buildings and such.