

Linux actually has a lot of people that get paid to work on it, especially nitty-gritty stuff like the kernel and drivers. Lots of multi-billion dollar companies rely on that stuff, so they often have some of their employees work some or even all of their working hours on FOSS.
Linus Torvalds himself is an employee of Red Hat, developing Linux is his entire job.

Sweat is a perfectly normal process, though. Being able to sweat a lot and having it evaporate quickly (little bodyhair compared to most other mammals) is one of humanity’s big evolutionairy advantages.