Most big companies were around for a long time before Bootstrap/foundation even got started. Guess which company had existed for several years already before Tw

Most big companies were around for a long time before Bootstrap/foundation even got started. Guess which company had existed for several years already before Twitter Bootstrap came out? If the had perfectly good in-house CSS frameworks, there's no reason to switch to Bootstrap. Bootstrap is a cookie-cutter framework, it is significantly more bloated than in-house frameworks that are tailored to only have code for the things you need (assuming you have competent devs). The same applies for performance, modularity, and extensibility.