You can normally fix bad code - fixing bad data structures is not usually easy or even possible. It's why I've still not fully bought in to 'release early release often'. I prefer to defer releasing for production use until really satisfied with the structures - this way you have no barrier to ripping the foundations up. If not 100% comfortable with the model - prototype a bare metal improved one (schemaless DBs ftw)…
I'm in the position of maintaining a legacy codebase. I feel like I've shown up half-way through a game of Jenga and management still wants me to play the game with the same speed as the guy who played the 1st half. Meanwhile, he's been promoted to start work on a brand-new Jenga tower since he's demonstrated such remarkable success in the past. I just want everyone to stop playing Jenga.
Unfortunately as you pointed out, especially in large companies, people can get promoted before the deficiencies of their previous work become clear. This leads to people never learning because the feedback loop is too long, or worse, they never deal with their past code so are oblivious to all its shortcomings and just think they are awesome. Also management tends to reward based on accomplishments today without an eye for costs to be born down the road, which gives perverse incentives to "get it done" programmers who leave mountains of technical debt in their wake for others to deal with.