As open-source software we want everyone to contribute to the ongoing improvement of GitLab.
Gitlab is a SaaS company who also provides an open source set of software. If you don't want to invest in supporting up time - then don't sell paid SaaS services.
They need more users!
I feel like this is a non sequitur. There's no reason why breadth would increase outside contributions other than sheer surface area, but that relationship isn't very linear, especially if the surface area is being created by Gitlab rather than others.
Meanwhile, "polish" is often the unglamorous work which people typically don't want to do for free.
Try to imagine an exchange at Torvald's Bazaar and Emporium. Gitlabbers offer to work on the fun stuff and get paid for it. In exchange they ask everyone else to work on the boring stuff without being paid.
For some mysterious reason, this exchange fails to happen.
Thanks, I am now convinced that I'll never do business with GitLab.