Although I am thinking specifically of the Switch/DS as they are the only current consoles I know of that is using cartridges, it really applies to gaming hardware on the whole. I'm wondering if Nintendo's reason for cartridges could have something to do with their upgradability.

There is literally only one reason for thinking this: they did it with the SNES by adding unique elements to the cartridges itself for way better graphics on StarFox and Mario RPG, then there was the N64 Expansion Pack which somehow did something - does anyone know what actually went on here? Was the expansion pack really exlusive to cartidge technology?

Anyone have expertise on this?

The capacity can due to flash being shrunk and other techniques but the read/write speed can't due to the hardware bottleneck of the controller on the Switch itself.

The n64 memory expansion wasn't a cartridge, it was more of a memory module which the switch can't do due to technical limitations.

I don't think that the Switch cartridges can do that, as I don't believe that they connect directly to the motherboard. I know that there were SNES and Genesis games with chips inside them, but I am almost sure that won't happen with the Switch.

Technically. Yes. They can. The cards and cartridges aren't that different that it would prevent such a thing.

However... Back when Super FX was a "thing" TDP wasn't much of an issue, the chips only consumed a couple of watts, they could be cooled without active cooling, so it wasn't much of an issue placing them inside a small plastic box without air flow.

Fast forward to today... To accommodate a secondary chip with a sufficient level of performance to make a big enough impact to justify such an approach, just wouldn't be feasible in such a confined space without sufficient cooling.

Fixed function specific-task secondary chips are an entirely different matter though. Then it ends up being all about cost.
For instance you could have a chip in the games card with a special-purpose pipeline for texture decompression for megatexturing... But you won't ever get a second tegra GPU in such a small space.

Didn't realize this is technically "cards" we're dealing with now. Because of the different encasement?