It's worth noting that this recommendation has nothing to do with delivered power.... a 500W can handle most systems on delivered power.

This has to do with transients, the 3000 series cards have some massive transients that can easily trip OCP protection on powersupplies not designed for that kind of transient. A 700W powersupply is able to handle those transients much better than a 500W PSU is.

That is true, but it all depends on how much the rest of your system uses. If you just have a mid-tier CPU and SSD, you may find that the rest of your system only uses 200W, and you can fit a 3080 on a 600W power supply. There are multiple reports of high-quality 600W PSUs working, so YMMV.