Sadly, It's basic marketing.
People, especially the uninformed/teenagers who are their target demographic, like bigger numbers.
People will simply buy your product if you advertise that your product has a bigger number than previous versions(even if it is detrimental like it is in this case[can you imagine trying to legitimately use 10000 dpi? it's ****ing beyond belief])
This obsession with using ridiculous laser sensors with 6k+ dpi needs to stop, but I can pretty much guarantee it will not, because people buy the products.
The companies need to stick to using a DECENT sensor such as the 3090/3310/3888, and THEN focus all their efforts on making the mouse comfortable and aesthetically pleasing. Rather than designing a good looking mouse and just throwing in the highest DPI sensor they can find, despite it being riddled with flaws such as acceleration(negative and positive), smoothing issues, huge lift-off-distances.
Honestly, who can says they use, or know someone who uses over 2300 dpi and actually makes it work in gaming(what these mice are predominantly designed for).