Queueing is niche?

If you have to program ANYTHING that serves requests and has a limited buffer you enter the domain of queueing theory.

Processing internet packets? Queueing theory.

Developing a distributed system? Queueing theory.

Designing software to manage a call center? Queueing theory.

Shipments? Ticketing? Payments? A myriad of other things? Queueing theory.

Fun fact, while posting this reply HN redirected my to a page "Sorry we're not able to serve your request this quickly". Guess what would have helped?

Queueing theory.