Boredom is where a good deal of thinking happens
Ideas turn up in the gaps, and the gaps have been filled in.
Most people can name where their better ideas arrive: in the shower, on a walk, in a queue, half awake, during the drive home. What these have in common is that nothing was competing for the space. The mind was left to run without a task, and it went and connected two things that had not been introduced. This is not mysterious. It is what happens when there is room.
The gaps that used to produce this have been comprehensively filled. Every wait now has something available to occupy it, and occupying it feels like the obviously better use of the time. The trade is invisible because nothing is lost that you can point to. You simply stop having the ideas you would otherwise have had, and there is no way to notice an idea that never turned up.
Preserving some of this does not require anything dramatic or named. It is closer to leaving one or two ordinary waits alone: the walk, the queue, the ten minutes before something starts. It is genuinely dull at first, which is the honest report rather than a caveat. The dullness is the condition, not a side effect, and the return on it tends to arrive later and sideways.