The plan is basically to force all GeForce card owners into the larger (and growing) GeForce ecosystem, by giving GeForce Experience users exclusive access to new driver releases. You will still be able to download drivers from NVIDIA's website, but this driver release mechanism will fall back to a quarterly cadence.
One thing NVIDIA has made clear is that they’re sticking with their overall Game Ready driver release system – targeting frequent driver updates to line up with major game launches – and this includes WHQL certification, so this won’t be NVIDIA cutting back on WHQL releases despite the fewer updates to their website. However even with WHQL certification, NVIDIA’s frequent driver releases (20 in just over the last year, not counting hotfixes) have been both a curse and a blessing for their wider user base, as non-gamers use the same drivers. I get the impression that this change is in part driven by a desire to establish separate “gamer” and “long term” driver release cadences where non-gamers aren’t constantly being bombarded by Game Ready point updates that primarily affect software they aren’t using.Gamers wishing to get access to the latest driver releases will need to download the GeForce Experience tool, and NVIDIA is clear that this is part of a broader effort to promote the tool as a critical part of the GeForce ecosystem. Downloading the tool will not be enough though, you will need to create a GeForce account but it's not exactly clear what NVIDIA's plans are for this registered userbase.