Great article for easing readers into the concept of saving, and his situation is very relatable, as you said.
The article doesn't say how long he's been saving or what his salary is, so for all we know, his savings rate could be 50% or higher. He's banked $50k (when you include paying off his student debt), he's probably only been working 2-3 years, and I'm guessing that an entry-level writer doesn't make more than $45-50k. That could easily put him anywhere between 40-70% of after-tax income.
Nice to see a story about this without a barrage of angry comments. Probably because there's enough evidence of certain indulgences (e.g., daily coffee) and because there's no mention of early retirement.