Look to other operating systems that evolved their UI in similar fashion and a few of their dominant software players over the years:
Windows-Office, Quickbooks, Quicken, IE/Chrome/Firefox/Netscape (which have shifted favor over years, but not because of UI changes in the OS)
Mac OS (X and classic)-Adobe PS, Illustrator, ProTools, Office
UI changes, even major ones, have had little to no effect on the dominant software titles for those systems. There have occasionally been new categories of software introduced. For instance, high quality video editing software for the home market, which was made possible by better home cameras and major advances in speed and resources of home computers. Pervasive internet allowed the browser wars to happen. It wasn't minor UI changes in the OS that allowed new players to come onto the scene, it was major technological advances.
If you go back far enough, you can argue that the change from command line to GUI allowed for just such a revolution described (it definitely did: Wordstar/Wordperfect lost to Word, Lotus lost to Excel, AutoCad nearly lost its throne, etc.). But, nobody in their right mind is arguing that iOS 6 to iOS 7 is the difference between DOS and Windows 3.1 or between an Apple IIe and Lisa or the first Macintosh.
History isn't always the best indicator in the tech industry, but in absence of other indicators, I'll bet on history repeating in some form.
The chrome around something like Photoshop is a small part of the entire experience, and unlikely to change a purchase decision. This is not true for many smartphone apps, where the look and feel is one of the key features and selection criteria. Apps that don't update will feel crappy and old and that'll put them at a major disadvantage.
This will be a chance to catch any "lazy" dominant apps if they don't upgrade soon enough. I'm not sure if there are any dominant players that are lazy - seems like you'd need to keep on your toes if you're gonna stay dominant. So not a whole lot might change, anyways.
There were some notable changes in the Classic-to-X change. Quark XPress replaced by InDesign, BBEdit replaced by TextMate. Probably a few others, too.
Adobe's tools stood unchanged in the X switch, in no small part because they got X versions out pretty quickly that felt relatively at home. Quark, IIRC, took forever to make an X version, so Adobe was able to bring out an X page layout app and eat their lunch. Of course, it didn't hurt that everyone pretty much loathed XPress, especially its heaviest users...
While I agree there were some shakeups, I think it also proves my "major technological change" point. Mac OS to OS X was a major technological change. Went from a pretty, but clunky, single-tasking, OS to a quite advanced UNIX-based multi-tasking OS. UI was the smallest of the changes that happened there. There was also a major processor and architecture change in that story line. Big differences. Having a native app was mandatory to take advantage of a huge jump in capability.
Look to other operating systems that evolved their UI in similar fashion and a few of their dominant software players over the years:
Windows-Office, Quickbooks, Quicken, IE/Chrome/Firefox/Netscape (which have shifted favor over years, but not because of UI changes in the OS)
Mac OS (X and classic)-Adobe PS, Illustrator, ProTools, Office
UI changes, even major ones, have had little to no effect on the dominant software titles for those systems. There have occasionally been new categories of software introduced. For instance, high quality video editing software for the home market, which was made possible by better home cameras and major advances in speed and resources of home computers. Pervasive internet allowed the browser wars to happen. It wasn't minor UI changes in the OS that allowed new players to come onto the scene, it was major technological advances.
If you go back far enough, you can argue that the change from command line to GUI allowed for just such a revolution described (it definitely did: Wordstar/Wordperfect lost to Word, Lotus lost to Excel, AutoCad nearly lost its throne, etc.). But, nobody in their right mind is arguing that iOS 6 to iOS 7 is the difference between DOS and Windows 3.1 or between an Apple IIe and Lisa or the first Macintosh.
History isn't always the best indicator in the tech industry, but in absence of other indicators, I'll bet on history repeating in some form.