UI Deploy

What are the pain points and considerations when large companies/applications move existing products into a single responsive codebase? The largest challenges are seldom technical. They are often cultural.

I have worked on a large number of responsive web projects; everything from small boutique sites, to large content driven websites, e-commerce sites and web applications. I relate this fact not to blow my own trumpet; merely to inform that I have not arrived at these conclusions based upon a single market area or industry type.