Most probably a commercial pricing separation.
Domestic residents mainly need fast download speeds.
Maybe it becomes a more commercial requirement for high capacity upload speeds... so they'll charge more for that service.
Also might deter high capacity zombie networks, as domestic hardware tends to be less protected from cyber criminals
There are technical reasons why upstream is limited, all working on premise that residential users need a lot more downstream than upstream. Typically they only give you enough upstream to cope with all the return acknowledgements to achieve the full download speed.
Yes, inevitably we are usually looking for more download capacity than upload. Maybe in the commercial world you can choose your split? It certainly limits domestic users from running busy servers at home (not that I want/need to do that). On the ping rates I recall that in 2014 when we had fibre to the home at a different address we had pings in single digit milliseconds. Nowadays we have to hang our broadband off a 4G router with an outside passive antenna so things are very different ... though not dreadful by any means: