When async payments are implemented, it would be theoretically possible for mobile wallets like Phoenix to provide a static invoice (with blinded paths, etc.) to receive zaps on. It would only require an LSP for a non-custodial assist, but otherwise would be self custodial.

The main hurdle is accumulating enough pending zaps to fund a new inbound channel (approx 10,000 sats / $3 today).

Maybe bootstraping precoiner users will always have to be custodial, but with a path to self custody.