And then what? Yes, an Alabama community collage can't pay for a language teacher, that's a fairly normal problem for community collages. It does not suggest there is somehow a market failure.
PS: I think you miss understood my upper bound. I doubt people want an immigration policy based on filling any jobs that pays more than ~30k/year.
I don't see what "market failure" has to do with the H1B at all. Just because the market worked correctly doesn't imply that the outcome was desirable.
Some distant collage may chose to pay for such a teacher and then gain students from the community collage who want that instruction. So, in that context your community collage bringing in the H-1B may end up costing an American a job. It could also depress wages for teaching that language discouraging other students from learning it thus extending the shortage over time. Alternatively, the demand may simply not be there for the language at which point the collage is better off paying for a different type of instruction that more students want.
In the end your H-1B is clearly a boon for that collage. However, if may end up hurting the country overall.
The H-1B system short circuits that mechanism. The salary doesn't rise, and young people are savvy enough to realize once an industry starts using foreign workers it never will.
Voila! Permanent shortage of Americans willing to do that job.
It might be a better outcome for native translators who see higher demand increase their salaries. The market has to be fair for all participants. Salary will never increase with demand, if increases in demand are always undermined by bringing in H1B workers.