New records on Wendelstein 7-X

Looking at the picture, I wonder if complexity of these devices will significantly be reduced once it finally works. I assume a lot of the bells and whistles are needed to find the way, but once it's found..

Your question reminds me of the image showing how SpaceX raptor motors evolved https://imgur.com/a/4w3q3lS

I'm not keen on the idea of applying a 'keep subtracting things until it blows up' mentality to fusion reactors.

You could probably summarize the history of bridge-building as "keep subtracting things until they don't stand up anymore."

Building bridges (and large structures in general) has always been about the tension between over-engineering (for safety) and under-engineering (for cost/aesthetics).

The Brooklyn Bridge is massive; they'd never built a bridge like that so they over-engineered it. But once they saw that it was more than strong enough to stand up, the next bridge was lighter. And the next one after that was even lighter. And so on, until a bridge collapses because some new factor came into play (e.g., harmonic resonance).

Source: To Engineer Is Human by Henry Petroski--one of my favorite engineering books.