Comment by seiji

I'd guess that's because they have so many condidates to pick from.

Exactly. It's the Big City Dating Problem. There are so many people to pick from, nobody wants to compromise to build a relationship. Just leave at the slightest sign of something not being 100% what you want and on to the next one since there are 20,000 other acceptable people within walking distance.

if you have access to a compiler and internet

It's not exactly that, but you often don't realize how many micro-checks or micro-confirmations you do while programming. In the absence of any "is this okay so far?" feedback, you're left second guessing yourself and reading your solution redundantly to check for any errors your daily automation would catch immediately by default.