This whole article reeks of imposter syndrome. Of course, it must be the case that all the devs who are more productive and impactful than the author are actually secretly very bad, and that the author's inability to understand technologies like Rx, validation and testing frameworks is actually a hidden strength because it makes him some perfectly interchangeable lowest common denominator developer. I hate/hated working with Rx, but it is fundamentally not challenging or complex.
This story is common because the types of people who are capable of single-handedly building large parts of a software product in a short time are naturally the ones who are "hyper-productive" and leveraging a tonne of different technologies and paradigms. The unexceptional "slow and steady" devs are usually not capable of having that kind of impact. When devs like the author do manage to single-handedly deliver entire codebases (e.g. over long periods of time), they are typically just as bug-ridden and unmaintainable as what the "rock star" devs produce.
Ultimately, the onus is on businesses to avoid crutching themselves entirely on a single developer's output. But there are a heap of shitty businesses that have no method for delivering software other than to let singular, highly motivated and passionate developers "go HAM" on the codebase with no oversight. These businesses deserve to fail, and the unmaintainability of the code base after the departure of their key players represents the correction of a market anomaly.
>Then suddenly, the frontend lead quit for greener pastures
What does this even mean? Key personnel do not "suddenly" quit.