They don't.
They play uber-tier pokémon, which is as much 'pokémon' as dual lash prince and nine obliterators is 'warhammer 40,000.'
The only people who actually play pokémon are those who got into the craze ten years ago, and now play tournaments on a frequent basis, scary americans, looking for asian children to cam and microphone with, and people who pretend that they're asian children.
Pokémon, just like classic games such as chess, is very easy to 'win,' but extremely hard to 'play.'
The match-ups get pretty intense, and there are even tiers and special clauses in place, to control the extremely lax foundations of the game.
To 'win' at pokémon, you load up on three mewtwos, a darkrai, deoxys, and arceus.
To 'play' pokémon, you go online, and have the above team utterly crushed by a spiking skarmory, a tanking blissey, a wobbuffet thrown in for laughs, a level 1 rattata with focus sash, a metagross with agility, and a bronzong.
Pokémon requires extensive amounts of time to do well in. The monsters come with unique stats, decided by luck and their parents, a special class of stats that you have to train up yourself, the good moves are expensive and rare, and the good monsters take forever to level up.
Add to this the fact that you HAVE to breed monsters that are any good, and that breeding - as listed above - gives you slightly random stats.
To give you an idea of how long raising just one monster takes, when I made my lucario, I went through 64 eggs before I aquired one that I deemed to be useful.
Each egg takes about five minutes of playing to hatch, and then you need to level the critter that comes out up to level 10, so you can cauge its usefulness.
A little kid could never, ever figure this out, and they never, ever do, either.
Only when they go online, and promptly have their all-offense teams picked apart, do they start to wonder, and do some research.
GT isn't aired anywhere in the world, because every single person currently living, or deceased, considers it a massive failure.