> in every single case I’ve seen, the developers who broke their local environments that badly had significant skill deficits which affected their general productivity. Investing in training paid dividends far beyond not having to deal with their local environment getting hosed since they also stopped creating massive security and performance problems in production.

I mirror this sentiment.

Another one that I've commonly seen: a bit of a yellow flag if a developer is struggling with Git. Becomes a red flag if the issues continue to happen after training. Usually means they don't understand other technical fundamentals.