They won’t, because specialization is a key aspect of capitalism.

This is why companies outsource anything. Google, Inc. is big enough to own farms and ranches to grow the food eaten in its cafeterias. They could make trucks to transport that food. They could operate factories to make cutlery, etc. Why do they instead choose to pay layers of margins to layers of middlemen?

Absurd example? How about Apple? They outsource production of their chips, instead of capturing the margin they are currently gifting to their partners. Why?

Delta Airlines doesn’t operate oil fields or even refineries even though a major cost of their operations is jet fuel. Why?

Once you can reason through these very simple examples, you will understand why enterprises are unlikely to walk away from SaaS.