Because it's the industry standard, and I presume because it's still quite good. The only modern thing I have to compare it with is GIMP (probably not a fair co

Because it's the industry standard, and I presume because it's still quite good. The only modern thing I have to compare it with is GIMP (probably not a fair comparison), but when I last used Photoshop it was already nicer than GIMP is now, and that was probably about 20 years ago.