B1M covered this. The video has a fun animation of the political history too:

https://www.theb1m.com/video/italys-12bn-bridge-mystery

Loved that one. We need something like this for NZ's south and north islands and so far ships are by far the best option.

Maybe some semi submersible, low-safety tube for cargo could make sense tho, but I'm not holding my breath.

New government cancelled $1.45b ferry replacement project for cost blowout and everyone expects it to cost even more.

It might be too short for a tunnel, the dive on the island side would be too steep for trains.

But that’s just an engineering challenge so relocating and reclaiming some land so it fits would be a better idea.

Seabed is deep and problematic to build a tunnel.