Google will now publish new source code to the Android Open Source Project twice per year, down from releasing source code for every quarterly Android release

Samsung and some other phone manufacturers have deals with Google to access code before public release

It doesnt fall under unfair advantage because partners like samsung are on the same level because they too get updates sooner ( through deals with google ). However, this will be a huge blow towards custom roms like lineageos that will now be way behind on updates compared to the rest.

But in the eyes of companies and manufacturers they arent competitors, they are leaches.

And before anyone flame against me, im typing this from lineageos, and will do so for a loooong time

Custom roms will have more issues with this. Manufacturers like Samsung have deals with Google and will have access to the sources more often. Custom roms won't have this access. I personally went back to the stock Pixel rom, and rooted it to still have acces to all of my modifications through Magisk modules and such while being able to stay up to date.

Why rigged? Shitty, yes. But they developed something in house and are under no obligation to publish it until they publish a product that contains said code. If they use a license that permits it not even that.