The whole game was broadcasted through satellite, the only copies would either be in Japanese satellaviews (If those had storage), or at Nintendo themselves (If they kept a copy), so it's not surprising that a vhs was the only way
Nintendo had a stake in the company doing the broadcasts but is extremely unlikely to have retained copies of the levels.
The only way to have retained the levels is by having received them by satellaview and then disconnecting the device, for 25 years, and hoping the memory isn’t too volatile to recover.
It’s extremely fortunate that some people recorded levels on VHs and that those VHS weren’t damaged or lost.
This is honestly incredible work being done for preservation. As usual, it's being done by fans and not Nintendo. It's a travesty that Nintendo can't be bothered to do more than the bare minimum and put the Satellaview content on SNES NSO.