This is a very lofty ideal. Especially something like Google assistant as a system default. That would require significant system-level changes that gave an application/service low-level access to your device. I just don’t see that happening.

There may be small variations in pricing, but the reality is more likely developers and app companies will keep pricing the same and pocket the App Store “fees”.

That’s what this is. The app is is just making use of the new API.