IBM had cafeterias, but they were not free, and they served standard "cafeteria food" that you might find at a hospital or school of the era. When I was at IBM in the early 2000's, the vast majority of people either brought lunch from home or went out (despite there being nothing within walking distance -- you had to drive 5 or 10 minutes to the nearest options).
As far as I know, Google was one of the first to offer food that was tasty enough, healthy enough, and cheap enough (free!) that nearly everyone ate at the company cafes on a daily basis.
Which campus? That doesn't match my experience in Austin at all, where most people ate the cafeteria even though alternate options were available with a very short drive, and the food was pretty good. Maybe not as good as Google's food at the time, but probably as good as the food at Google the last time I visited. And the food was decently subsidized (I'd eat breakfast there for $2). In Austin, Moto and Centaur known for having really good food, but IBM's food wasn't bad in the early 2000s. On my team, I think one or two people packed their lunch and everyone else would eat at the cafeteria except on special occasions.
I've heard from people who stayed at IBM that the food declined to cafeteria food quality over the next ten years, which led to the cafeteria basically being abandoned because people ate out so much. But that's actually counter to the narrative in the post — IBM had decent food before Google, and then some time after Google's IPO, the food declined to became standard cafeteria food.
https://en.wikipedia.org/wiki/Charlie_Ayers won a cookoff and made the Googleplex well known for food. Employees brought their kids for dinner. People from other companies angled for invites to lunch. I once realized I was in line behind Vint Cerf (Vice President of Inventing the Internet). Ayers moved on, but I think Building 43 mid-campus still hosts the enormous "Charlie's Café."
For a while, another building was notorious for serving sushi but only admitted their Android developers, because Andy Rubin was paying for that himself.
My experience (not IBM) is that there was not free food that varied a bit and different groups tended to cluster. At a company I worked at for abput 13 years, the engineers and product managers tend to favor the pizzeria which was run by a local pizza shop.
I've never had free food routinely except customer briefing center or some other lunchtime work function. Rarely went out unless it were a short walk. (The brief time I worked in downtown Boston with no cafeteria is pretty much the only time I went out for lunch routinely.)
Per another comment, my sense is that brown bag lunches used to be more common and most people stopped doing that.
As far as I know, Google was one of the first to offer food that was tasty enough, healthy enough, and cheap enough (free!) that nearly everyone ate at the company cafes on a daily basis.