It’s not that bass is more pronounced on the outer grooves versus the inner grooves, it’s that in the outer grooves the stylus is moving with greater velocity. this allows for a wider frequency response, both bass and treble can be more extended, and better sound quality in all ways, compared to the situation in the inner grooves, where the stylus velocity is reduced due to the reduced circumference of the LP at the inner grooves. As someone else aptly mentioned, it’s analogous to using tape to reproduce sound: high speed wide track tape is sonically superior to low speed narrow track tape for similar reasons related to the physics. To put it another way, it’s the law.
