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.)