Sadly Gimp is no alternative for people who want to buy Photoshop and Creative Cloud.
While I agree that most private users and to some point professionals can also accomplish the same results in Gimp as in Photoshop stuff like Bridge, the Creative Cloud and all those tools around the core applications makes the suites so valuable for designers that just do not want to roll their own sync / management / foo solution with even more software.
it's very possible that gimp might not be able to cut it for a lot of creative professionals, especially if they already have a lot of process and money invested in the adobe stack.
it's definitely my experience that a lot of more of my professional/creative friends rely on photoshop than gimp.
with this latest push to 2.8, i'd say the gimp folks still have a bit of kick in them and it's hard to argue with their licensing strategy. since the latter is what the original article was addressing, offering up the gimp as a good alternative seemed prudent. and, possibly, if facing a situation where i couldn't get photoshop licenesed over the weekend, it seems gimp would do in a pinch.
I've used GIMP for as long as I've been making websites it seems (about 12 years) and it works fine. I'm not a graphic designer though, so I'm not doing anything radical.
