I love how this very specific topic is posted in an Autism community and not any of the tech communities and yet it's getting potentially better engagement than if it was posted to a Linux/IT community
But onto the subject at hand, I work at an MSP at the moment (and probably not for long due to management issues) and the one thing I've noticed is that the MSP industry is all about risk, and deploying something they've not deployed to customers before is a huge risk. They'd much rather work with "the devil you know" than take the risk on something they haven't worked with yet. Commercial vendors also have the benefit of being able to hawk stuff onto their support to free up your own techs to take more tickets (and therefore make more money) plus of course the extra cost to customers is either a non-issue or a plus due to more margin (because everything an MSP sells you is sold with a margin, usually ~20%)
I will say, this experience has further solidified my belief that paying for outsourced services will cost more than doing it in-house for most businesses. About the only way outsourcing makes sense is if you literally don't have enough work to hire one dedicated employee to do the thing.