SWEs who don't touch infra show up because universities today pump out a lot of book-smart real-world-dumb graduates.

I don't think so. I have my areas of expertise and of course in a pinch I will pitch in and try to help any way I can, but I've always found my best work is done in a team with fairly well defined roles, a healthy respect for each others' specialisms, and an enthusiasm for short bursts of collab/pair coding and longer stretches of solo(ish) work.

I have fond memories of the team that worked across three time zones so I would get up to a set of well-described problems that I would solve in the morning (so satisfying), then a nice stretch of feature building after lunch, then a burst of pair coding with my newly arisen colleague, then maybe finishing with writing up any roadblocks or requests for the next person. I got very used to identifying blockers that were out of my area and would be better solved by the domain expert, and also a LOT better at ticket writing. It was a really, really productive and rewarding workflow and one of the key points was not getting bogged down in stuff outside my areas. We also all really appreciated each other because we all experienced each other as magical elves giving answers to hard problems in exchange for answers for easy problems! ;)