Another relevant aspect of Japanese management is the enforcement of consensus decision-making, which blunts the influence of the highly competent and incompetent.

Measuring ability is a lot more tricky and has more to do at times with your ability to manipulate optics. I'd understand it as more reliable and a gradual way to increase scope and responsibility. You'd only want to go faster if you want to chase money and promotions at a pace that is faster than normal, which may not be realistic in this market (or in normal market conditions generally).

> Measuring ability is a lot more tricky and has more to do ~~at times~~ with your ability to manipulate optics.

fixed it

Another way would be to narrow down to the top 2 candidates and then decide by a literal coin toss if they are equally worthy of the position.

> Westerners often laugh at Japanese companies privileging seniority over demonstrated ability

Unions in west have traditionally been built around seniority as well.

Yes, but union seniority is about getting paid more to do the same (or less) work; not about being promoted into different jobs.