Yup, but you need to involve yourself deep into quite the diverse range of programming, computer science, math and physics questions to be able to even read the specs, much less implement them. Codecs involve highly arcane math, an emulator not only needs to take care about the CPU but a whole bunch of side chips and associated timings, compilers are an entire field of academic study, and to work with LTE or anything RF in general you need a solid background in RF hardware electrical engineering, RF propagation, antenna theory and god knows what else, just to be able to have a "testbed" that works with your test device but doesn't shut off service to everyone in a few hundred meters around you.
This kind of mental flexibility is what I really admire.
It's just the average thing you learn going through EE or CompE, plus a knack for turning specs to code.
Don't get me wrong, I find him to be an elite dev, but more for the incredible ability to hold a spec in his head in sufficient detail - and do that multiple times.
