The tx/s itself is fast but the Ui aka applications built on the chain has other factors such as bandwidth and others. The applications are limited in function-if you read the steemit blog they often talk about server changes plus tweaks increasing the efficiency of the site not the chain.
Also the number i gave is theoretically possible. I think only half of that is actually possible. Why? The nodes have to have enough data,ram, bandwidth and storage just to support that amount. Due these factors the chain can't actually do the number but it can but just harder.