Whoa there, you seem to have gotten your things_used_to_be_better metaphors mixed up:
DOS: install program by copying a bunch of files to a directory. Start program, won't work as it needs something in config.sys. Add that something, reboot PC, try again and the program now complains about not having enough low memory. Fiddle with expanded/extended/extruded/exploded memory to get those extra 15 KB which the program needs. Reboot PC, the program now works but that other program which used to work doesn't anymore as the special something in config.sys conflicts with its own very special something.
Modern OS: install portable application, problem solved.
DOS: install program by copying a bunch of files to a directory. Start program, won't work as it needs something in config.sys. Add that something, reboot PC, try again and the program now complains about not having enough low memory. Fiddle with expanded/extended/extruded/exploded memory to get those extra 15 KB which the program needs. Reboot PC, the program now works but that other program which used to work doesn't anymore as the special something in config.sys conflicts with its own very special something.
Modern OS: install portable application, problem solved.