Some people are not comfortable rooting the phone. They don't know how, or don't want problems, or don't want to invalidate support, or don't want to be stuck without updates, or don't know which one, or are afraid of damaging the phone. There are lots of reasons NOT to root.
I have also seen nothing to indicate that PDANET nor Easytether even work on Evo with 2.2. Even if they did, they require proprietary software on the computer side (which is annoying).
Looks to me like Sprint has disabled USB tethering, even though it was my understanding that we would be allowed to do it. I thought I read that Sprint would charge for the multiuser WiFi hotspot, but would allow single user USB tether at no extra charge.