I also suspect people balk at infrastructure because it means learning a new and complicated thing to solve their problem, but the shape of the solution is the

I also suspect people balk at infrastructure because it means learning a new and complicated thing to solve their problem, but the shape of the solution is the same whether they build it in their application as a library or whether they avail themselves of off-the-shelf infrastructure offerings (although there are some problems that can only be solved by infrastructure). Either way, you have to understand the solution at a high level, and I think much of the balking at infrastructure is really just balking at needing to understand the fundamental nature of their own problem.