This could be used as an argument against every effort that ever led to anything good in the world.
It's not that there aren't times and places it might be appropriate, but I think it'd be better to say precisely what and whose effort you wish to spend on something better and what that better thing is.
There's room for lots of people to pursue different, complimentary goals. If you really hope to tell other people that they should spend their energy on something other than the things they have chosen to think are important, you'll need a stronger argument than vague hints of mysterious opportunity costs.
Attention of people currently inside the community doing outreach and outside the community is finite. In analysis of their outreach efforts, I'd hope that they would know what the trade-offs are. I don't. Hence the question.
For me, both the assertion that no opportunity costs exist and the assertion that the/a top problem faced by an upstart systems language is the lack of representation in their community of people with attributes orthogonal to language development strain credulity.
It's not that there aren't times and places it might be appropriate, but I think it'd be better to say precisely what and whose effort you wish to spend on something better and what that better thing is.
There's room for lots of people to pursue different, complimentary goals. If you really hope to tell other people that they should spend their energy on something other than the things they have chosen to think are important, you'll need a stronger argument than vague hints of mysterious opportunity costs.