Taking three consecutive car parking spaces and building a roofed cage for secure bicycle parking on them would allow like 15 people to park their bike. That would cost 3 - 15 = -12 parking spaces. Yes, negative cost. Once you start seeing the solutions rather than focus on how bad things are, you'll see that bicycling is ridiculously efficient in almost any metric.

You can hem and haw about how efficient it is, but for most commuters the theory of efficiency doesn't matter; the actual implementation does.

When my local supermarket, the retail stores, restaurants, etc. have bike parking that is secure enough that I don't have to worry about a $1500 e-bike getting stolen, I'll get one. But they don't offer it, so I don't.

The option to treat it like a motorcycle would help. You'd get a VIN, title, registration, and a plate.

Licensing bikes is hugely contentious, but in the case of expensive electric bikes, I do wonder if those benefits would start to out weigh the downsides for some people.

As an aside, in my opinion, electric bikes are probably the most practical form of transportation available right now for most urban communities. They climb hills, go pretty fast, can offset the rolling resistance of fat confidence inspiring tires, are smaller and easier to park than a motorcycle, are easy to charge, and have a manual backup in case of battery depletion. I love two-wheeled transportation in all its forms and think the electric bikes that are on the market now are an awesome middle ground between motorcycle and push bike.

I think the key word is "option". In no way should we make registration of bikes compulsory. But at the very least I would like to insure something worth over $500-1k.

Bike insurance is already available for those who want to buy it. Registration has no real bearing on insurance.

I lock my bike with both a strong U-lock and a thick cable lock. Never had it stolen, even when I spent a summer in Baltimore. (Though I would take the bike in at night.) You don't need to have impenetrable security, just better security than the bike next to yours.