> I'm not even 100% certain there's really much of a specific reason why there has to be a low hard limit on file descriptors
Same reason disks have quotas and containers have cpu & memory limits: to keep one crappy program from doinking the whole system. In general it's seen as poor form to let your server crash just because somebody allowed infinite loops/resource use in their program.
A lot of people's desktops, servers, even networks, crashing is just a program that was allowed to take up too many resources. Limits/quotas help more than they hurt.
Same reason disks have quotas and containers have cpu & memory limits: to keep one crappy program from doinking the whole system. In general it's seen as poor form to let your server crash just because somebody allowed infinite loops/resource use in their program.
A lot of people's desktops, servers, even networks, crashing is just a program that was allowed to take up too many resources. Limits/quotas help more than they hurt.