I think you've essentially described Ring's business model, with the exception they first offered video doorbells (our test of both models: The $28 Million Video Doorbell Ring Tested, Ring Pro Tested) and have added surveillance cameras recently.
There are ONVIF-compatible video doorbells available like dbell in the market too, but no considerable marketshare success yet.
As for commercial surveillance companies expanding into the doorbell market, several have moved into the higher-end, commercial targeted video intercom market. For example, Axis recently purchased one such company (see: Axis Acquires Intercom Manufacturer 2N) after releasing their own models (see: New: Axis Video Intercom), so what you describe is essentially happening just outside the typical residential space.
(Notably, Mobotix has has a video doorphone for years, with a steep pricetag and challenging integration options.)
Several have noted Hikvision has begun showing video doorbell options at tradeshow stands, with widespread release pending.