Your very broad question, presents with a very narrow, specific salary chart.
you have done some research and arrived at a very small niche of Federal/VA management level Pharmacist (GS 15) salaries. Having worked at the VA, I can tell you, GS 15 doesn't come easy or automatic. When I was there, a staff pharmacist would start at GS 9, clinical maybe GS 10, and I worked with career (35yr) R.PH.s that hadn't made it to GS 14. This is not any indicator for a ceiling, or norm for max salaries.
Then there are pharmacist that go beyond any salary ceiling.
The former CEO of WellStar Health System (now with 16 hospitals and 25000 employees), Georgia, was a former retail, independent Pharmacist for many years. NOW making about 1 million a year plus stock options as CEO.
My personal hero, Don Panoz was a retail pharmacist in Philly. Invented the patch, founded Mylan Pharmaceuticals, then Panoz Motorsports. Passed away in 2018 with a net worth (well north of) $500 million.
If you are researching Pharmacist salaries, looking into pharmacy school, it would make a whole lot more sense to look at starting pay, retail vs hospital. Then average staff pay. And prospects for job availability.