Unless you are trying to stream 4K video to well over 20+ devices at the same time.. and these devices are connected via ethernet, you'll never need 1 Gbps download bandwidth as a residential customer. The 500 Mbps (and 300 Mbps) is more than adequate for most uses.. even 100 Mbps is adequate for most residential uses. It's the upload bandwidth you should focus on... the 300/30 plan w/ 30 Mbps upload is more desirable than the current plan offerings w/ 10 Mbps upload bandwidth Cox is offering. If you are on the 300/30 plan now, stay on that plan for as long as possible. Buy your own DOCSIS 3.1 modem and keep that plan!
Something to keep in mind regarding "slower" speeds. It is unlikely you will ever get 1 Gbps bandwidth using WiFi... even the new WiFi 6.. in a real world setting w/ walls, ceilings, interference, etc... to a single wireless device. Now add more devices to your wireless network.. I think you can see where I'm going with this.
As for "slower" speeds than what you are paying for, you most likely have legitimate complaints about your service as the Cox network could be highly congested in your area. However, keep in mind that networking "quantity" (i.e. more bandwidth) does not equate to "quality" (i.e. low latency - the speed at which your device receives the answer to its network requests). I'd rather have high "quality" 100 Mbps service than low "quality" 1 Gbps service.
If I could get the 300/30 plan, I would sit on that forever.
