I'm kinda curious about this too. But then I'm always amazed at the enormous workforces these tech companies have, and I'm sure they cut them as thin as they can. Like adobe has 30,000 employees & some blogger estimated that 1/3rd of their workers are actually working on their software. I use their software sometimes and I really haven't noticed many changes to it over the years, except recently with the ai stuff. Like from 2015-2020 I can't think of any major things they added to adobe illustrator. I guess making and maintaining software is hard.
Adobe has a shit ton of product lines, people think of it as just the core Photoshop, Illustrator, etc., but just go look at how much random stuff there is: https://en.wikipedia.org/wiki/Adobe_Inc.#Products
That's in addition to running the big SaaS offering of the creative cloud and all of the other SaaS's (behance, adobe express, adobe stock, etc.).
All of those include software engineers, SRE, support staff, PMs, etc.. Then there's the massive amount of sales staff, go to market, etc.
There's also a lot of R&D and domain experts, stuff like Adobe Firefly? That was spun up in like a year apparently, probably continuing existing in-house research.
I fully agree most big tech companies are pretty bloated. But FWIW a lot of my time at SaaS companies, especially in the B2B space, was spend working on features for larger customers that most others would never use or even see. Like, yeah, product X isn't that complex, but $BigCorp wants to use it in their private cloud, or needs it to be single tenant, or needs these audits done, or want their $Gov client to use it. Now you have a ton of work for zero visible changes.