Ruin Explorer
Legend
I mean, it's too soon for us to say that. We need more information.it only seems they are separating it this way to help new players make smooth decisions.
How it's presented in the DMG and PHB could make an insane difference here. Like, let me give best/worst case:
Best case - The PHB mentions that Custom backgrounds exist, and tells you to suggest ideas to the DM and they will help you come up with a Custom background. The DMG does not present Custom backgrounds as an "optional" rule, but as a default rule, and offers guidance on how to make them work, and doesn't say "You don't have to use this"(obviously rule 0 exists, but there's a huge difference between default rule and optional rule - one you rule out, the other you rule in). The DMG also presents a bunch of examples, including modifying existing backgrounds in very simple ways like changing the stats.
Worst case - The PHB makes absolutely no mention whatsoever that there are any other background options, and acts like this is all there is, and maybe hints that you could find more in other paid books. The DMG presents Custom backgrounds as a strictly optional rule, that you don't have to and probably shouldn't use, and presents either no examples, or only some bizarre example like a creepy evil background that sounds NPC-ish.
Now, I'll be honest, in a scale between the two extremes, I genuinely expect 2024 to be closer to Best than Worst, but... I didn't expect them to do something as dumb as get rid of the Tasha's approach to stats in the first place, so I have actually been too positive in my beliefs about how 2024 would handle backgrounds so far!