Increasing the magnification, with everything else being equal, will also increase the weight of the scope.
A big part of the cost hike in LVPOs when they increase the magnification is to also reduce the weight elsewhere to offset the increase in weight from the optics element associated with higher mag range.
If you ever used magnified optics, you will know that as you crank up the magnification, the observable area aka field of view, also shrinks correspondingly.
High powered dedicated sniper scopes offset this with having a big objective lens, but LVPOs don’t have that feature to save on weight, so if you crank them up to 8 or 10 power, your field of view is going to be very restricted. That makes it much harder to find targets, plan shots and track targets on anything that isn’t stationary. Which isn’t great for a semi auto DMR, which is why LVPOs are not cranked all the way up to max magnification as often as you might think. Certainly not when it’s your only optic. If you run a second, offset red dot, then you tend to keep your LVPO at max power and use the red dot for close range and fast moving targets.
You need a more precise firearm and different ammunition in order to utilize higher magnifications. 1-4x you can put on 5.56 carbines, where 8x would be kind of pointless.
Also keep in mind, that just looking at your target from a kilometer away isn't enough. You need to actually hit that target. And that takes a lot more training because you have more variables to consider at longer ranges. It's the difference between Designated Marksmen and Snipers.