The median consumer for an ISP is someone who pays for a service and asks for the wifi password printed on the back. Thats about it. Maybe they change the password through the app (TR-069) if they want to change it later. Having something like this working 24x7 while also being able to afford to run a cable to the home is quite challenging. I hate pretty much most ISPs for having a good service but terrible equipment. But I know most of my friends and relatives really don't care. They just want to use it for work or browsing / binging and thats about it. With fiber this is more messed up because now they are being sold gigabit plans when in reality a 100-200mbps connection would be enough if the home was wired correctly and all devices received a good wifi connection with a good router connected to some APs / mesh with maybe something like SQM.
Getting rid of a GPON router can be challenging now that everyone is moving to fiber.
-For one, you could get banned for having a problematic transceiver.
-You might be able to spoof the SN and even MAC and PLOAM password but even then there is a GPON ONU and OLT incompatibility problem. Nokia OLT for example can be notorious while some OLTs only work with their own brand ONUs.
-Finding the correct VLAN is also tricky and sometimes different VLANs are used for different services like POTS which means your GPON bridge needs to be able to do correct pass through after registering instead of registering on just one VLAN.
ISPs should just provide a GPON SFP bridge to consumers with the router it plugs into that has a TR-069 configured so that the ISP can also swap routers as and when they get upgraded while keeping the SFP bridge constant as the cost of router would then decrease without having to need a GPON ONU to be built. Not to mention the software gets less complicated without GPON on the router end.
https://hack-gpon.org