There are hardly any slots on motherboards too now these days. One network card may fit next to the GPU. All kinds of limitations to nvme SSD speeds and GPU bus width may start applying just for doing that.
Exactly, as long as GPUs keep swelling larger and larger, pcie cards just aren't going to be practical.
It's crazy that X670E literally has multiple chipsets daisychained together ostensibly to increase expansion capability and yet there's less and less expansion available to end-users. And what there is, is almost entirely blocked by the GPU these days. I would love to see a board with tons of pcie slots attached to the chipset or PCIe switches, but, it wouldn't make the GPU go away for those users who want a discrete GPU.
The only real viable solution I see is thunderbolt, move as much as possible out of the case and break that expansion out as external ports. And tbh the PCIe add-in-card form factor just isn't working for GPUs anymore, the GPU needs to become a standardized module that is connected separately (via riser if desired) and it probably needs a 48V rail. The GPU being 3-4x the TDP of the CPU but completely dimensionally unstandardized and running crazy currents at 12V is not sustainable.
There are so many motherboards that fit exactly what your ideal state describes. They just start to get expensive.
As an example, I'm currently running 2 3090ti's on a MSI board in addition to 2 10GB PCI-Express cards, + 3x m.2 SSD's and I am not even close to fully utilizing the lanes OR other premium slots (like SATA)
If room is an issue, get a larger case or there are also offset/vertical mount options for things like GPU's.
Looks like the current max for any AM5 or LGA1700 board is 5 pcie x16 slots. And of course they won't all be full ones, they'll be some x4-in-x16 (which still is better than nothing, because slot width does affect electrical delivery capability of the slot). And using M.2 slots often eats up some of the pcie slots as well.
Looking at one example - Gigabyte B660 DS3H - you get 1 pcie 4.0x16 and the rest are PCIe 3.0x1-in-x16.
The promise of having these super-powerful chipsets has supposedly been that we can put more stuff on it. Same thing for pcie 5 - stuff doesn't really need it yet but you could put a bunch of slower stuff on switches and get a lot of the capability of HEDT out of a consumer board. That has not materialized, even a $700 consumer board is still pretty much intended for one gpu and maybe 2 nvme slots.
If you want a bunch of pcie expansion you still have to go to HEDT or server, but AMD killed HEDT and then lost interest and went outside to ride bikes. So now it's only server.
ROMED8-2T is the closest thing that exists to what I want, but, the promise of X670E and daisychained chipsets and superfast pcie is that I shouldn't have to buy an Epyc to get some decent number of real x16 slots, or at least x4-in-x16 or whatever.
