At this point in my life (49), I could not consider going to any MFA program that I would have to pay for. As a single father who works on average 60 hours a week, my obligations far outweigh my ambitions. I would consider attending a fully-funded program (provided I could get in) simply to be afforded the time and space to read and write.
A strong second reason, which you discuss, is the opportunity to make connections; both in terms of having the support and motivation of a cohort doing the same thing you’re doing, as well as the opportunity to professionally network. Writing *is* a business and while it’s possible to network online, there is a great deal of value in “face time.” Also, that commenter is wrong, by and large the people teaching in these programs *are* successful writers. Having them in your corner can indeed be very beneficial.