I don't think it necessarily has to be about kickbacks - it's also about acclaim and reputation?

In software, you talk about a project you headed or a new feature you developed when you're looking at promotions. In a political career, a new bridge or a new project has more advantages than simply upkeeping an old one for basically the same reason - it can be associated with you specifically in a stronger way, you can talk about it as an accomplishment to more people. "I funded repairs so this bridge didn't fall" is a lot more of a non event, at least until the bridge actually falls and someone has to be blamed.

It's more that politicians respond to incentives -- repairing bridges requires money being spent and taxes going up, since states can't run at a deficit for very long. Often this angers voters. Similarly, people get pissed off about what we refer to in Michigan as "Orange Barrel Season" when you cant' get from here to there because of the construction snarling traffic. As a result, it doesn't build goodwill to maintain infrastructure before it's at the verge of catastrophic failure from a political standpoint. On the other hand, building new freeway through mostly farm fields has concentrated costs (the farmers losing land, who are then paid fairly well for the loss) with obvious benefits to everyone. It's pretty "no downside".

In Michigan we've also run into issues where infrastructure crumbles before the bonds that built it from scratch are paid off, which then causes significant pain in paying for repairs, since it requires all new taxes or significant other service cuts. This was one of the main arguments in the 2018 gubernatorial campaign and then in the early part of Whitmer's term.