NoM L1 will be for consensus only. No bloat, no bull shit. Settlement only (mostly). We have a few contracts on the L1 for AZ, HTLCs, PTLCs, and the bridge. As kaine has stated, we can expect L1 to setting > 100K TPS.
The SC layer will live on the L2 along with Unikernels (I think). So we need an L2 to scale the usability of NoM, not necessarily the TPS.
The NoM L1 will be for settlement only (with the except of a few contracts) to keep the protocol light and fast. There is no bloat on the L1. It simply settles TXs. Poon talked about variations of this in 2018. I started the talk where he talks about how the L1 is used for consensus.
The L2 infrastructure will be used to scale functionality - SC Layer (WASM), Unikernels, etc… The functionality will appear on higher layers so the L1 can adjudicate disputes only. Poon was talking / thinking about this back in 2018/19.
If you want to learn more watch all Poon videos on youtube about Plasma.