I’m in the same position as you, and I agree wholeheartedly. The one thing I’ll say is that I think 20 years is optimistic.

I’ve been involved in a few huge, greenfield projects that were mostly building new things from the ground up. There was an air of “true” building around. But it was astonishing how quickly that faded away. It took less than a year after our first launch for a lot of people to start leaving the team, citing reasons like their job was now just drudgery maintenance work or small feature adjustments, which is definitely less attractive and inspiring.

And that is reinforced by career paths as well. See: the trope about Google promotions based on new launches, not bugs fixed. And people definitely idolize “the engineer that built Linux” more than “the engineer that has patched 1000 linux bugs”.