I remember playing Subspace (one of the first multiplayer internet games and now called Continuum) in mid 90's with a 14.4kbps modem and my ISP used a satellite link which delivered 850ms to server. It felt 10x more usable then Uber.
It's pretty easy to make your own error/sequence checking for UDP.
So what's the drawback of not using UDP?
At which point you've just re-invented TCP - and likely without the 30 years of weird/odd edge condition handling that TCP currently contains.
Found something interesting here http://gafferongames.com/networking-for-game-programmers/rel...
In order to "error check" it will need to ask for retransmits of packets with errors (which will interrupt the steady flow).
In order to sequence check it will also have to request retransmits of missing packets (which will interrupt the steady flow, and here you'll get the same queue wait incurred by more recent packets while the retransmit occurs so you can reassemble the original sequence).