Yea, I got similar advice during undergrad (back in the nineties, when dinosaurs roamed the earth): The web is a toy. It's not for Serious Developers™. Serious Developers™ do real time embedded systems, device drivers, systems programming, control systems, etc. Don't worry about HTML (which isn't a "real" language for Serious Developers™). Learn C and assembly, and microprocessors. Then Netscape happened and I found myself wondering if I bet on the wrong horse....

2 decades later I'm still not sure!