I highly doubt chiplets will get dropped. Too easy to bin from. Although laptop silicon is monolithic. Also has less L3 cache, For lower latceny.
I did a bit more research..... erereerer nope I'm still lost in this bottleneck. I looked again at the threadripper deep dive on techpowerup. The 3960x bandwidth starts just slightly faster than current AM4 chip with it a about 66.5 GBs up to 105 GBs something like almost 60% increase. The only thing that changed really drastically was minimum frame rate went up to 30% on average. The overclock was still about The same 8% average increase with memory tuning. The latency can come close to AM4 In ns. I read some people where having better performance with ram speeds on threadripper in 2:1 with speeds above 4200. Back to the laptop's monolithic die the smaller caches have it about a 10ns drop off current 3000 series. Unfortunately the review I looked at only had a 1660 gpu in it. Couldn't really see much improvement with 50ns latency vs 62ns. I think the split amount of L3 cache has an added latency.

Imo 10ns down ain't going cut it when intel is around half of 62 or less.

Do We know the penalty for a L3 cache hit in the other CCD? (L3 cache it is not split by CCX is it?)

We know three things about Zen 3. 1 it's CCX is now going to be an octocore. 2 it's L3 cache is one big pool instead two smaller split up. 3 aren't they increasing the FPU by 50%.
I'm starting to believe the load stores aren't big enough even for Zen 2. Like there waiting for new data, that's just not there.

Zen 2 seems to a wall on frame rates on lot of games regardless of clock speed.