For 50gb/month, you'll need 2 - 3 hotspot accounts. It won't be inexpensive. While you're right that technology has advanced quickly, cellular data demand has exploded, causing the wireless network to choke in areas of heavy use.
Just try to access data networks at a major sporting event and you'll know what I mean. Cellular infrastructure has not kept pace with demand. As a result, all wireless carriers have implemented procedures to limit usage. Even those that "claim" unlimited data plans now throttle speeds on the biggest users, whether on grandfathered unlimited plans or not.
Personally, I don't see this changing anytime soon. Cellular bandwidth is expensive, given the vast area of the US. As long as demand expands so much, wireless companies will not keep up. Expect prices to rise.... :-(