Hiring irrational players, or forcing rational people to act outside of their own self-interest is not a winning strategy either.
There is nothing wrong with building stuff, or career development. There is also nothing wrong with experimentation. You certainly would not want to incentivize the opposite behavior of never building anything unless it had 10 guarantors of revenue and technical soundness.
If you need people to focus, then you need them to be incentivized to focus. Do they see growth potential? Are they compensated such that other employers are undesirable? Do they see the risk of failure?
Some people do things for other reasons than maximising their monetary gain at every step; there are all kinds of motivations out there including liking solving problems
There's also a huge spectrum between "pick a job that's good for your career" and "at every step of the way I'll do whatever is best for me, the company and my coworkers be damned"
If you can't see that, just be open with it in the interview process