Come be a DSP engineer. I take FFTs of IQ data almost every single day

Some variation of QAM will always be used in communication. As soon as you deal in with EM-waves, be it physics, engineering or even biomedical stuff you will have to deal with complex numbers, which by extension is dealing with I/Q signals. You probably don't need this for programming a server or a website, but it's indispensable for signal processing.

Work on low-level software for communications, especially RF, and you will see plenty of this stuff.

Not just RF, also optical communications. Really, the only domain left where PAM transmission is used is baseband communication for electronics, and datacom for optics.