How does one "master" the technique though? Anakin least of all. Like okay, we can imagine Qui-Gon discovered the technique, meditated on and developed it over years of his life and managed to get it right on his only chance to put it into action. Honestly, it is probably something that has long been attempted and he is just the first to get it right. Cool. And he used his ghost to teach Yoda and Obi-Wan, who also prepared over years to attain this state. But Anakin was not on good terms with any of them until his last minute shift. So... how did he even know about the technique, let alone master it?
If in doubt, you can always play the old "Chosen One" card to hand waive that sort of thing away.
Mr "highest midichlorian count in history" Skywalker might get a free pass just because he's magic.
Which on balance probably means it was pretty lucky he did a redemption arc before he died, otherwise they'd have been stuck with an evil maniac in their immortal ghost club.