I've been surprised by how comprehensively NFT activity has shifted to L2. 

In a little over a month we've seen +90% of Zora activity move to L2. It's very early, but it's looking like we're seeing activity we wouldn't have otherwise seen on L1. Optimistically, that means expanding the market!

What needs to happen to accelerate this new behavior? eg is bridging too much friction?

Precisely this. And the problem is not only technical.

The gap from no-coiner to coiner (eth) is huge already. It's going against many psychological factors (unsafe, associated with scams, risky).

And then we tell them, hey, you gotta move your hard earned funds to this network, because the main one is expensive.