Because they often change skills/devotions around, causing one to continually have to respec skill points. I have a few level 85’s that after many tweaks, cost 25,000 per respec point. If you are resetting a build, that can add up to quite a bit. Ultimately, if that is the case, I just reroll and level to 85 in 3 days or so, allowing me to start fresh again. I do agree with the original poster to a degree however, I would like to see a “tonic of skill reset”, just make it extremely rare. They already have one for devotions, add one for skill points.