Let me address something which is not explicitly mentioned in other answers. Job issues exist, and they exist not only for category-theorists or the like, even much more ''working'' (in the sense of MacLane) pure mathematicians are struggling. In my opinion, the reasons (and possibly the solutions) for this are socio-political in character, we can discuss that elsewhere.
To return to math, I have not seen all the comments, but. First, using HTT to prove something, understanding the proofs of HTT, and doing HTT-level of papers are three different levels of difficulty. It is very instructive to have a problem from another field for which you would need higher categories, then it becomes much easier to navigate in the literature to find what you need, or ask precise questions to the experts. Later steps seem to follow as you get sucked in. On the go, you will perhaps start to value the aesthetics of the state-of-the-art in higher category theory, happy days. Even if your pure interest is category theory or something of that form, it helps. You learn more about (higher) category theory by applying it.
And, we have to remember that it has been only 20 years since the active development of the field. Various papers which followed since the HTT book show that more thinking leads to more transparency. You mention that there is no Bourbaki for homotopy theory; certain people believe that it is yet to come, and working towards it represents a big prospect in mathematical foundations.