There’s no need for them to move to FTTH; 99.9% of homes don’t need more than 10-20Mbps upstream.
I was on 1000/40 for most of my history with them ($100+$50) now I have 2000/100 ($150+$50). I would be fine with 40Mbps upstream unlimited; the issue is not the throttling but the threats resulting from bait-and-switch.
The problem with cable internet is that the shared medium (coax segment) has relatively little upstream bandwidth, shared by 100's of users. FTTH has much more bandwidth and a smaller amount of homes sharing it. Typically there is a passive splitter / fiber distribution for 8 to 32 homes, at least an order of magnitude better than cable.
I switched to fiber a few years back. But at one point during covid, my cable modem upstream was getting less than a megabit (I was paying for 500/30.)