It's not just mobile networking but residential ISPs in general have better IPv6 support. In the US, Comcast was one of the first big IPv6 deployments, in Europe CGNAT+IPv6 is common in many places.
Meanwhile corporate IT for business and education networks have less incentive to upgrade and typically lag behind in adoption in general.
I've been running full dual stack for >15 years now. It has become second nature by now and I'm slowly testing IPv6 mostly, but so far it's just easier to deliver dual-stack to all users instead of dealing with workarounds to make the last few non-IPv6 capable services work without native IPv4.
Meanwhile corporate IT for business and education networks have less incentive to upgrade and typically lag behind in adoption in general.