1) Those building railways, roads, cities, redstone circuits, efficient automatic farms.

2) Those playing on "PvP" servers all day, attacking each other, fighting in arenas, clan wars, etc. (If you hear a constant "click click click" noise, that's probably them)

The ratio of type 2 to type 1 players is probably something like 7:3.

Type 2 relies on servers, while type 1 can be is usually done alone (on a server it typically ends in drama).

None of us can commit the time we used to commit to games (a few of us have kids), but I reckon we each probably put in half hour to an hour every day or 2, and the occasional 2-3 hour session per week while doing work on another screen or on hold on the phone.