[vito]

What you aren't including is the chronic cost of maintaining the status quo, which is the entire reason for making the change. Sometimes making no decision costs you more than making a risky one - and if the decision is risky, you'll want to investigate it first.

During that investigation you discover things (like having to implement your own components) and try to account for how much they'll subtract from the time and energy you save. If the calculus works out, you keep going. If it doesn't, you stop. We kept going, and now we can ship complex features and optimizations to both UIs within a day or two.