Why people that play rapid play so good

They are many reasons why rapid players play so good
1.when you play a ultrabullet,blitz,bullet game you are always pressurized which makes you lose often
2.some players are so good with long matches they focus only on rapid and spend more time on it
3.To train like a grandmaster you need to play long matches which make sense why people that rapid are good

some times you get lucky and win matches but for me they rarely happen