I agree with you, and disagree with all of the quoted statement. IBM did survive the PC even if they got out of the PC business. It's not clear if the "PC guys" are PC makers or those who make software for PCs, but either way they have indeed survived. Especially if you include the Mac ecosystem. And "web guys" will certainly survive the post-PC world. There will be adjustments and adaptations to new environments but great folks at Mozilla and other forward thinkers are ensuring that the web will survive and become a good platform for apps.

https://wiki.mozilla.org/B2G

As is always the case few things ever kill the old technology, they simply provide another way to do things. Native apps are not going away on any platform, and web apps will only get better in the future as the web becomes a better platform for making them. The browser will continue to be one of the most important native apps.