Nah, SSI is interesting but it has absolutely 0 need for a blockchain. It's just another case of a solution looking for a problem.
The only reason anyone cares about blockchain is because of the ability to speculate. Remove that and it's a tiny niche tech - which certainly has use cases but nothing you can build a Facebook or Google around.
A blockchain also allows software programs to interact with each other in an uncensorable way, and ensures that those programs operate the way their source code says it does. It may be a niche technology, but I think these properties are useful for a bunch of types of apps.
