From the Scamoramic to 7 Gbps is quite the leap. Do your devices have ad-cards?
I think the first step is to determine how many devices will be on your network. After your count, what will those devices do on your network? If your devices will be simultaneously streaming UHD video, multiply your count by 15 Mbps. That'll give you an idea for bandwidth. Add another 15 for those other suckers on your network: refrigerator, thermostat, doorbell, lady robot, etc.
If your house is prone to weak signals, I could understand more powerful antennas; however, I agree with Mouth of $700 being an overkill.