> developers and managers repeatedly act as if established best practices do not apply to them
... and rightly so. A junior programmer might be better off always following "established best practices", but I expect any developer worth their salt to be able to know when to break the rules.
"Best Practices" are not always well defined or applicable. In some cases there are conflicts among different practices. Even worse, there are cases where one person believes something is a best practice and another believes it to be a bad practice.
The reality is that there isn't really such thing is a 'best practice.' There are only practices that have been found to be 'less wrong' than other ways, and perhaps even 'useful.'
Whatever your development practices are, the important thing is that you have and maintain the flexibility to adapt to what the particular situation needs.
... and rightly so. A junior programmer might be better off always following "established best practices", but I expect any developer worth their salt to be able to know when to break the rules.