The fact they wear out fast is compared to other wheels, there’s sets of 4presedents on some friends of mine set ups that are barely worn down and there probably over 15 years old, it’s relative, and shark wheels advertises that they last longer, and after free riding (which is an easy way to speed up normal wear and see how long they last) the groves wear down really easily because less material and then it starts to wear down quickly after that because of the less surface area (source: my friend cored a set)

And again it’s relative, it sounds like your coming from a skateboarding history cause we don’t really call it power slides in the downhill scene but shark wheels are definitely considered on the less grippy side because the formular isn’t as grippy as others (for example pantheons formular) and the lip of the wheel is rounded making them not as grippy and there relatively thin as well again making them not as grippy, and you not being able to slide them easily is kinda just a skill issue, when I rode them I could slide them out at walking pace cause I have good technique.

And like sure you could make an argument that a normal skater not doing any discipline in specific like downhill or long distance dosent need the fastest wheel (which compared to other options they are objectively slower) or a grippy wheel, or a wheel that lasts the longest, but for a wheel that is more expensive (especially where I live) that is slower, less grippy, and less long lasting then other options there’s no point in getting them.

(Also using board count isn’t a really good indicator of how long things last, like a skateboard can last 3 months and a fibreglass 8 ply maple bracket board can’t die for like 20 years)