My understanding is that 6G is expected to make use of a good decentralised fibre network, with small radio units at the end points of this network providing the wireless contact point. With interoperability being on the books for 6G, whoever controls the fibre network is in for a lot of money (unless the article we're commenting on is right).
So it might make sense for operators to focus on developing fibre regardless.
Yes, this distributed radio idea is a feature of both 5G and 6G. You stick the dumbest, dullest parts of the radio electronics up on the tower and trunk them all back over fiber to an aggregation/control point a few kms away, and then trunk the agg points back to the packet core a few hundreds of km away. That needs a lot of fiber to carry the backhaul. I dont know if operators are thinking of using this fiber to also incidentally deliver broadband service, but today that doesnt happen: for one, oftentimes the mobile operator doesnt own the fiber, they just lease it.
So it might make sense for operators to focus on developing fibre regardless.