Across three full rewrites of the same core product, almost nothing survived except the internal tooling — the scripts, dashboards, and CLIs the team built for itself, not for users.
That’s not a coincidence. Product architecture gets rewritten because requirements change. Good internal tooling gets built around a constant: the team’s own workflow, which changes far more slowly than the product it supports.
If I had to bet resources on what would still be true in two years, I’d bet on the shape of how the team works before I’d bet on the shape of what they’re shipping.