So, one thing spelled out clearly in the final arc of the Clone Wars cartoon was that the reason why Qui-Gonn didn't manifest a "force ghost" was that he died before he'd completed his research into the possibility. He could, at most, manifest as a disembodied voice that only the very sensitive (like Yoda) or the specially trained (like Obi-Wan later on) could hear. Yoda went on to learn the secret himself and pass it on to Obi-Wan. One presumes Anakin was such a whippetydo prodigy that once he figured out such a thing was possible, he just willed himself to keep it together in the afterlife. But Qui-Gonn missed his chance in life, so didn't manifest as a force ghost in Return of the Jedi.
The implication I took from that was that, had Qui-Gonn lived longer, he not only would have figured out the secret of maintaining his personal identity upon joining the Cosmic Force, he would have taught others. Within a few generations, every Jedi worth his lightsaber would be confident of an immortal afterlife in the Force, rather than the somewhat cold comfort of knowing his Living Force would join the Cosmic Force in an anonymous way.
Clearly, the Cosmic Force saw that coming and wanted no part of it. Anakin wasn't spawned to stop Palpatine...Anakin was spawned to stop QUI-GONN. Heck, Palpatine might've been goosed along by the Dark Side because it wanted no part of Qui-Gonn's plans either. Anakin was born to be found by Qui-Gonn, to distract Qui-Gonn (note how he ended up becoming Qui-Gonn's Padawan just as Obi-Wan was about to graduate and leave his old master free to buckle down on the whole force ghost research project), and if things worked out nicely, steer Qui-Gonn into increasingly dangerous situations and get him killed. (This works particularly well if while the Light Side was aiming Anakin at him, the Dark Side was specifically grooming Darth Maul to be the specific instrument of QG's demise.)
Everything else, including the possibility that the Force kinda wanted Jedi ranks to be thinned, was just gravy once Qui-Gonn was safely dead.