Even today the GSL (the most competitive individual league for SC2) just had its last championship and is cancelled while the ASL (the most competitive individual league for SC1) is still going strong. However it was much bigger before SC2's release.
Not to take anything away from Serral, he's a fantastic player, but Korea was never as invested in SC2 as they were in SC1. Players were getting by on extremely strong mechanics and there wasn't the kind of professional team infrastructure that existed around SC1.
Personally I think that was a technical limitation of the first game and a huge ergonomic improvement in the second.
Other things like having groups of buildings on hotkeys means you don’t have to go back to your base to order more units and set the rally point (where units go when they’re built) for all those buildings at once. This makes StarCraft to be an insanely micro-mechanic intensive game at high levels.
In the early implementation of Warcraft 1 (1993-ish) I made it possible to select all the units on-screen at once with drag-select, and even more by scrolling and shift-clicking or shift-click-dragging.
Allen Adham (president of Blizzard, and exec producer for Warcraft) argued convincingly that only 4 units (for War 1) should be selected at a time. I argued against it pretty vociferously at the time … and in later days (post launch, most likely) came around to his way of thinking. Attacking with a superfluid of units takes less skill than selecting troops in small batches, and so requires to use more intent & skill.
Warcraft 2 allowed 9 units to be selected, and StarCraft more.
Starcraft 2's F2 to select the whole army on the map is the other extreme and where it eventually landed right (I think that was introduced in a SC2 expansion, it was not a launch feature?)
On the unit selection, a personal view on the situation is that nigh-instantaneous unit commands and obedience approaches valley of the dolls. It becomes too much like Wargames calculating theoretical death scenarios, abstracted from the issues of actual army logistics.
It takes some non-zero time. Units are not always doing exactly what they're supposed to. The fog of war is often worse not better than the game abstraction.
Maybe others... that said, anyone that pays attention to both games knows that the lack of complexity in unit and macro mechanics in SC2 leaves room for other actions, such as more intense "micro" mechanics. Neither game is more demanding then the other, it turns out in both games you never run out of things to do.