Is 8GB of Apple RAM equal to 16GB? I doubt that. But it is definitely more efficient, and with dynamic caching, even more efficient than we've seen it become.
Is it equal to 12GB of PC RAM? 10GB?
Apple isn't going to stop starting at 8GB anytime soon. They know that bumping up the low end will increase costs across the board...and especially since going to Apple Silicon, 8GB is a good amount if you're a simple user who doesn't run many apps at the same time, or you don't have 40 tabs open.
It's actually good they aren't just going to 16GB, because it incentizes them to make the system as efficient as possible, which pays dividends by making all Macs better machines. And if you are reading this, you're a power user—you come to Macrumors, come on—so you already know you want at least 16GB, so pay the tax.
It's not smoke and mirrors—Apple Silicon does use RAM better, and 8GB is increasingly enough depending on what you do with it. Bleating over and over that Apple "needs" to give away double that amount is silly...they will only do that if they look at what their average user is doing with the machines, and seeing that those folks are starting to have real memory pressure at such a level that the floor needs to be raised.
And when they do—count on it being 12 GB, not 16.
In the meantime...just buy your damn RAM up to 16GB if you are obsessing over it!