ARRIS G36 issues!

I decided to buy my own gateway after renting the Xfinity gateway for a few years because the xfi-pod (range extender) failed after almost one year. Since it was under warranty, xfinity replaced it free of charge but that one also failed after about 6 months of use.  Xfinity said I would have to pay for a new xfi-pod since the warranty on the original pod had expired. Go figure.  Super frustrating.  I decided to buy my own gateway to improve the range and coverage in my house.  I am paying for 1 gig download speeds so I decided to go with the Arris G36 since it's been "approved by xfinity" only to find out that I only get about 1/4 of the speed that I was getting with the xfinity gateway.  This Arris G36 is supposed to have the latest software blah, blah, blah.. that is 10x faster than the old software.  Super annoying.  Upon further research it seems that xfinity hasn't pushed out the software so I'm probably running the older DOCSIS 3.0 and not the newer DOCSIS 3.1 which is probably causing the super slow speeds.   Is Xfinity dragging their feet with updating software for 3rd party gateways so that we won't buy our own equipment and have to continue paying them $15/month?  Xfinity already has a terrible reputation, so you'd think they would try to do the right thing here and create some customer loyality by pushing out updates for gateways ASAP.   It kinda feels like xfinity is effectively throttling my internet speeds because I want to use my own 3rd party modem.