No one can really tell you this as it depends on future events. will web assembly stay supported, will web applications stay a preferred ui, etc.
on the plus, blazor unlike silverlight is hosted by a web standard (web assembly). yet while web assembly has been declared the future of the web, blazor is probably the most popular toolkit.
my guess is that web assembly applications will always be a niche. it is a compute sandbox that depends on javascript to access the dom or network.
the reality is that the web application development is a fast moving technology. you would hard pressed to pick any framework guaranteed to last. what ever you pick today, may or may not look so good 5 years from now. You need a plan to stay current. You should reevaluate your decisions on a regular basis.