Yes, it is sad indeed the things people toss out that are either perfectly good or can made near perfect with a simple fix.
Preventive maintenance goes a long way in my opinion, especially with vacuum bags, belts, filters, etc. I like to do things myself, and would always attempt to repair my vacuum before taking it to a repair shop; though I have this mentality with anything that I can read about or find out how to fix (toaster, hot water heater, hvac unit, lamps, etc.). As someone else mentioned, youtube and google have a wealth of information and someone has probably already had the same problem and posted about it online somewhere. Parts can be had inexpensively too in some cases. I think some folks do not want to take the time to even look up how to do it.