I think it's better to take a production line approach the way musk did with spacex rockets. That would give us a recurring fixed budget, career stability, and stable pipelines for training and research. It's bound to be far more cost effective and to have more benefits for society as a whole.
There's no good reason not to have a steady stream of space telescopes and rovers being sent out at a rate of once or twice per year.
With cost of launch to space finally coming down thanks to SpaceX & reusable rockets in general I would imagine this is how things will go much more often in the future.
Not only mass production but possibly cheaper materials, more in-space prototyping & less expensive ground testing and paper studies before launch.
There's no good reason not to have a steady stream of space telescopes and rovers being sent out at a rate of once or twice per year.