[labby5]

The M1x will almost certainly have 64 gb support, possibly 128. Apple has left Intel Macs in the lineup for customers who need features that the M1 has not replicated, like large RAM capacity and 10 gb Ethernet. The M1 macs are still better for 90% of customers, but the intention is to only fully phase out Intel Macs in a product line when Apple Silicon is better for 100% of customers, as they did with the Air. The M1x will fill out the remainder of the Macbook Pro and Mac Mini lineup, which requires 64 gb support. It is likely (though not a guarantee) that the M1x will also fill out the entire iMac line (excluding the education M1 iMac they have not yet released). That would require 128 gb support.

People seem to be under the mistaken impression that supporting higher memory capacities is hard. It's not. It's trivial. The only reason the M1 doesn't is because of how it's packaged, and they only chose to package it that way because the products they were intending to replace it with only need 2 memory chips. They did what made sense for the M1, and they will do what makes sense for the M1x.