Helping agencies build own SaaS - opinions?

Hey! I run a small product development studio and we've built a few software products for various companies over the last years.

Lastly, we built a SaaS for an agency.

I was wondering if more agencies think about starting their own SaaS? And would be willing to invest in an external software studio to help them?

In theory, this makes a lot of sense to me:

• agencies deeply understand customer issues (perfect place to start a SaaS)
• agencies can start charging for tools, instead of solutions (and thus scale better)
• agencies reduce risks when working with an external team (instead of hiring in-house devs)
• agencies (ideally) have some cash they can invest to build an MVP

Curious to have your opinions!