[nilkn]

There's an easy heuristic here. Look at a segment of the industry which is unambiguously not in a bubble and ask yourself whether you could get hired there doing similar work with a similar salary.

There's one hitch here: if the entire startup scene were to bust, there'd be a massive excess of developers vying for the traditional stable jobs at traditional profitable companies. This would significantly raise the bar for getting hired while potentially lowering salaries.