I think that open source licenses for complete software (such as SaaS components) for commercial entities have a one major purpose:
A marketing tactic. If I am open, it is easy to discuss it everywhere without paying for it.
I think that if you are short on cash, open source is the way to go to get adoption faster. If you have endless money, then there is really no reason to open source it (except edge cases, like shared protocols, libraries, etc...)
Even though it may seem harsh to apache 2.0 the code, no one will steal it since you are maintaing it, essentially paying to keep it on your turf. Reasons for not stealing:
1) Security CVEs and patches. No serious company will use it without these.
2) Bugs, if I take it I will have to fix it.
3) Merging changes. If the source is branched, I will have to get people to move to my project. Otherwise, I will have to employ people just to merge the changes all day.
4) Authority. I would argue that if you do not control the narrative of the project it is essentially similar to abandonware of the project. What would a customer/client prefer more? to use the original product or some copy of it? If you are the Authority that inspire people, they will not go to the competition.
I remember in the past the open source were thought of as communists. I think that we are far from that, and big capitalist companies knows how to profit from open source (even Apache 2.0 and MIT).