Also the capacity is significantly higher with L2 included, and increasing rapidly.

With zkrollups and a decentralized sequencer, you basically pay no penalty vs. putting transactions on L1. So far I think the sequencers are centralized for all the major rollups, but there's still a guarantee that transactions will be valid and you can exit to L1.

Scaling is improving too. Rollups store compressed data on L1 and only need the full data available for a month or so. That temporary storage is cheaper but currently is still duplicated on all nodes. The next L1 upgrade (in November) will use data sampling, so each node can store a small random fraction of that data, with very low probability of any data being lost. It will also switch to a more efficient data storage structure for L1.

With these in place, they can gradually move into much larger L2 capacity, possibly into the millions per second. For the long term, there's also research on putting zk tech on L1, which could get even the L1 transactions up to 10,000/second.