It does.
The solution to this problem is to run Vault in high availability mode[1]. This will have a set of stand-bys that can take over if the leader goes down. The idea is to unseal all the stand bys, and if the leader goes down, the standbys take over, and the sealed one can be unsealed at some other future point.
Security-sensitive things have been an interesting UX challenge for us, but this compromise comes at an expense of UX for a much better security promise. As one of the other comments says around this comment: without this feature there would be no real security for the stored data.