Why was Port forwarding moved to Xfinity's Controll?

it was much easier when it was under the Gateway's controll, (10.0.0.1 ) its rather confusing and irritating esp. with multiple devices or if a device has the same network name over diffrent connection types (Wifi vs LAN)

it was a headache to open up portsfor a game i play on multiple platforms "Warframe" on PC Switch and PS4, and for the PS4 it made me want to tear my hair out! in the device list i cant tell which "Sony Playstation 4" is the LAN listing. (my system's forwhatever reason been "Barred" by the gateway from connecting to wifi, it just wont connect) and it just seems to keep changing in that order between the 2 X_X..

Not that it matters past august as i plan to be out of this state "heck" hole, (and no dont please bombard me with "well you can move your service to the new address!" the friend im moving in with has verizon and thier area is under an exclusivity contract.) but Why was this done?