I can see why people would focus on the risk of a flashy explosion, but I think the real risk will be with the deployment process and having gotten everything right with JWST. ESA launches are very reliably, JWST is a one time design.
I think as long as we are using rockets to lift things from our world, there will be some level of fear of failure. After all, rockets are essentially an explosion attempting to be controlled.
The problem is that the technology that JWST is built with is no longer available. The development cycle moved so fast that the industrial bits needed to manufacture JWST are no longer there, even if we have complete and detailed plans.
Very similar with how building a Saturn V today is logistically impossible, even if we can build more modern, efficient and cheaper rockets.
There is not a single crewed vehicle in operation or even planned that supports spacewalks. If it's not next to the ISS, people aren't going to be able to fix it.
At best we could send a robot, which would probably be more easily operated from the ground.
There've been several proposals for an Orion-mated orbital module with an airlock, as well as an ESA one based around their ATV. After all, the eventual goal of Orion is to allow deep-space missions to asteroids etc.
Even coming up with something from scratch is unlikely to cost the $10B we'd lose from a failed JWST.
