Using on-page styles & scripts for entire website?

From observing dozens of my websites and their analytics, new visitors rarely browse more than 2 pages per visit and their return rate is even lower as no more than 10% - 30%.

Does this mean serving styles and scripts in separate files are actually a bad practice since HTTP requests are more expensive than data transfer?

By analytics, we can know that most visitors to my websites are new and first-timers and will never be again, therefore the separated styles & scripts are served to them once (or at most twice) and never again, so should I get rid of these separated requests once and for all and make all the styles & scripts on-page in one request?

Could this be any problem in terms of user experience? Considering the analytics this should be good to user experience?