Why is Intel focusing on 40+ Golden Cove cores for SR instead of 160+ cores in the same die space using Gracemont? Just to be clear I'm not saying they should, this is above my pay grade but I know many here will have some solid reasoning for their decision to focus on Golden Cove for SR.
Im sure they're working on it, but it may be that they're still working on that chip. If they want arbitrary cores in such a chip to be able to communicate effectively it's a lot harder to do that when you have 160 cores than when you have 16 or 24.
Another reason is that such a product, while useful, is also going to fill a particular market niche. Some server software charges on a per core basis which means that having a lot of small, efficient, but less powerful cores isn't as beneficial as fewer, but more powerful cores.
Actually there is a reason to disable cores and the reason being not have to do with defects or the inability to reach a certain frequency.
Why do they disable the gracemont clusters? Because it gives them a reason to sell it at a lower price.
If they've saturated every level above that then yes they would do it just to create artificial market segmentation. I think that's more likely later on in the products life though since when they launch they'll have short supply and even if the yields are exceptionally good, they can always make the bins more aggressive until they get the kind of product mix that they want.
To draw a parallel consider Zen 3 right now where AMD hasn't released anything below the 5600. Eventually they'll put out some 4-core part for dirt cheap, but it's unlikely they get many chiplets that naturally need to be binned that way. Once the rest of the market is saturated they can start disabling more cores because they couldn't sell it as a 5600 so may as well try to make a buck on a lower end model.