If 90% of you customers are phoning to complain the service is down and they can't reboot the modem because the lights are turned off because of the power cut, you can't have skilled support engineers dealing with them. Setting aside the money, the engineers would just go stir crazy and turn into BOFHs.
The trick is to either vet your customers, or enable a shibboleet protocol
How do you propose filtering out the tech savvy vs. unsavvy folks needing support? I think a big problem with "tiered support" (shudder) is that the support folks on the 1st level are often less tech savvy than the people who actually need something fixed... but they deal with so many customers who don't actually have an issue to report that it makes it worthwhile.
Oh, the restart fixed youtube.com for you? Great! Have a wonderful day.
If something bad happens on their side and it does happens eventually, they must fix the problem by manually editing the system. If they don't allocate human resource for that task or their system is hard to edit by hand, they don't provide the support.