this really pisses me off because about 5-6 months ago I was doing an interview for a job that of course I did not get because old, and I talked about an instagram / branding startup thing I was the CTO of and main programmer in 2014 and how I made this build system to make sure that css classes and JavaScript objects were properly namespaced and how we made sure there was no potential collisions and the way we made sure exactly what scripts needed to be loaded on the page based on which of our widgets were on the 3rd party client site etc. etc. and at the end of it the guy interviewing me said dismissively there are tools that do that and everybody does that nowadays which I sort of had to agree they probably did because who knows, I'm not really doing that thing any more, and now it turns out they don't even.
on edit: fixed some grammar