I think this is the key here. Most engineers go through some gradual phases from what I have learnt, initial, when they are confident of being able to accomplish everything, second when they feel they now understand how things work and third when they know that there is a lot more to it.

This essay sounds more like a second phase. Rewriting something that you do not understand makes sense if most people on team do not understand it well, and are supposed to actively contribute to it OR you are at an inflection point where the choice of architectural or foundational decisions made back then become a bottleneck in every day performance or feature development.

Business is looking it from the cost benefit perspective and they would not approve it at the cost of company time and money if it doesnt makes sense to them. Your ability to fool them for your motivations may be a different angle, still they are the ones making the call.