What determines what is too high here? If it's about the cost of it (it costs Google/Apple much less money to build and maintain an ecosystem so they can "afford" to do it) wouldn't that imply that there is a huge market opportunity for someone else to build their own ecosystem and charge less? But maybe because that doesn't happen is proof that it may not be "too high".
Hmmm. Let's see what one would need to do at a bare minimum:
- start manufacturing phones
- build own OS (or fork Android)
- develop own SDK
- develop own online store infrastructure
- manufacture other devices (e.g. Apple) and/or develop other services (e.g. Google) to complete "ecosystem"
The barrier to entry in developing a mobile (and beyond) ecosystem is astronomical when competing with either Apple or Google. It's practically impossible to break into a multi-trillion dollar market when it's siloed to two multi-trillion dollar corporations.