If Nvidia were on the same node and increased die space to match M1 (ignoring the CPU portion of the die size), they would then be able to run at a lower clock with more compute units and probably match the TDP discrepancy.
An iGPU isn't necessarily slower if the system ram is fast, and M1 was one of the first consumer CPUs to move to DDR5. 3090 has 936.2 GB/s with GDDR6X, M1 Ultra with DDR5 memory controllers on both dies gets 800GB/s.
For the record: I was the first M1 recipient (temporary 16gb MB, stock issues). I needed an Intel MBP because Rosetta ain't all that. I opted for, and was upgraded to, the 32gb M1 MBP. I chose M1 over Intel because it was unbelievably faster for the form-factor. My original comment does not concern laptops. My PC is orders of magnitude more powerful.
TDP is physics. You all might perceive Apple as perfect and infallible and all so lovely, but physics is physics.
I use AMD, not NVIDIA. And "what if" is irrelevant. It's like intentionally neutering Zen2 by comparing it to Intel single-core (as was done all the time). The reality is absolute, not relative. Comparing effective performance, not per-TDP, is what matters to the user. And my network/gpu/audio drops on both my 16gb M1 MB and 32gb M1 MBP under load.
Seriously not buying that "Apple can do nothing wrong" bias.
Take those #Ff6600-colored glasses off. The M1 has unbeatable value proposition in a pretty wide market, but Apple couldn't be further from a universally good machine.
Performance per watt? I could see that being disrupted, but an iGPU in 2022 will be orders of magnitude less powerful than a dGPU, if wattage is ignored.