They have a vehicle that costs the average price of a new car. That was their goal with the model 3 when it released for 35k. Now the average new car price is 48k and a model 3 is 47.5k. The model 3 also sells hundreds of thousands per year and keeps increasing. They achieved their goal of an affordable mass produced car. So they followed through.

By tractor I assume you mean semi truck? Pepsi is taking deliveries in a few weeks. No one said anything about affordable since these are commercial products. So they followed through.

Solar is probably one of teslas least great offerings. But they have been providing solar roofs to people so again they achieved their goal. So they followed through.

Neuralink hasn't promised anything other than to continue to do research so there's nothing to have not followed through with.

Mars mission? Back in 2010 musk said it would take 10 to 20 years before they could send cargo to mars. We still have 7 years to see how that goes. As for spacex, since then here's a list of things they followed through on: reusable rockets, resupply missions to the ISS, carrying humans to the ISS, launch weekly, building falcon heavy (which nasa administrator Bolden called a paper rocket vs their real sls. Yet falcon heavy has been launching for 4 years and sls not once despite starting development first), private customer spaceflight, and they're currently working on that Mars rocket. So yeah I'd say that's a follow through.

Commercialized robotics is a relatively new thing they've started so can't say they haven't followed through yet. It'll take time. Could go like falcon 9 or could be like full self driving (which tesla has not followed through on).

Most of teslas mini projects have been followed through on. Solar? Yep. Battery storage? Yep. Supercharger network? Yep. Full self driving is really the only thing they haven't followed through on and has had enough time to say they haven't done so.

You say tesla would generate 20x to shareholders if they split all these projects yet neuralink and Mars missions aren't part of tesla. The rest of the things make sense to stay under tesla and not be separate entities.