Different Save Files, households no longer sync?

I'll try to keep this as simple as possible.

I've been playing for a couple of years, on ps4, have several game packs and kits. For the longest time you pressed the big green Play button and it brought you to the world maps and you picked a family from there.

What I would do is play and when I saved one family would be in Save File 1, another would be in Save File 2, and so on. Some were overwritten with new households.

So Household A would play and I'd Save to SF1 and from the map I'd pick Household B, play and save that house under SF2. But Household X might also be under SF2. 

I would also like to point out here I've never once used a cheat or a mod.

I haven't played in 6 months or so and noticed the big green play button is gone and now you just choose Load Game and load SF1. I played a couple different households before noticing, when I tried to invite Sims over that I knew where teens/adults, that they were missing. Going back to the Map and hovering over that house showed the Sim I knew as a teen as still a toddler. So it seems that the world syncing is no longer a thing? 

So I guess my question is: if I overwrite SF2 with SF1, will the households from SF2 be lost and all progress lost as well? 

Why did sims4 make it so load files don't run congruent with each other anymore? 

Households that are in SF2 that aren't listed as the "main" house can still be played in the save file and then overwritten later?

Can I go back to just having the big green Play button?