Resistance to anything has an evolutionary cost - the most resistant species tend to breed slowest, the hardiest environmentals even slower.
Organisms which can live in volcanoes usually die when given mild conditions but competitor species instead.
Your statement also begs the question: given we're assuming you can reasonably disinfect yourself, why not simply re-innoculate with an optimum colony of bacterial species and short-circuit the negative effects?
Leaving aside my pet peeve of people using "begs the question" inappropriately, your question is answered by the article.
An optimum colony of bacteria is hard to maintain and propagate outside the optimum environment--namely, on your skin. The colony also reacts negatively to being disinfected. The experiment is to establish such a microbiome and then leave it the hell alone.
Resistance to anything has an evolutionary cost - the most resistant species tend to breed slowest, the hardiest environmentals even slower.
Organisms which can live in volcanoes usually die when given mild conditions but competitor species instead.
Your statement also begs the question: given we're assuming you can reasonably disinfect yourself, why not simply re-innoculate with an optimum colony of bacterial species and short-circuit the negative effects?