In house developer's time certainly should not be spent converting a PSD file in to a full HTML/CSS website. If the designer can't build an HTML/CSS site its likely that massive chunks of usability knowledge is missing as well.
The thing that hit me about abandoning PSD mockups (coming from a 15 year Photoshop user) is not responsive design but high DPI displays. A lot of big companies still have terrible upscaled raster images on their sites. It is bad enough for logos, even worse for the site's UI. Sticking to HTML5 & CSS (with a backwards compatible design for the few users still on XP of course) is easier to build and ends up looking a lot better.
This is one of the nice things about the occasional comp delivered in AI. Its so much easier to translate assets to the web that it confounds me why AI wasn't the standard from the beginning.
I haven't used it recently, but a few years ago? AI was terrible compared to PS. I mean, I like vector graphics and was willing to struggle with a lot of pain for the advantage of using vectors instead of rasters for a project... holy crap AI was awful. Crashy, cumbersome, cringeworthy.
I'm an amateur, so I'm not going to be an expert on the professional features, but a few days with AI led me to go right back to Inkskape.
I have no idea why they put their resources into that thing over Fireworks.
The thing that hit me about abandoning PSD mockups (coming from a 15 year Photoshop user) is not responsive design but high DPI displays. A lot of big companies still have terrible upscaled raster images on their sites. It is bad enough for logos, even worse for the site's UI. Sticking to HTML5 & CSS (with a backwards compatible design for the few users still on XP of course) is easier to build and ends up looking a lot better.