Ultimately, you actually often need something like an IBM to be around to acquire your small company so you can run away with the money.
I disagree. From a marketing perspective, they are a company that is known to over promise and under deliver. Their marketing is vague pie in the sky without much to show for in the market. Watch this IBM ad and tell me what is it that this company actually does:
https://www.youtube.com/watch?v=gsEwmumEsKU
They are a company that fails to innovate, and fails to be relevant, yet they put a ridiculous amount of effort to try to convince people otherwise.
From a business strategy perspective, IBM has spun off or sold off most of their great product lines and business units. Some of which were failing under IBM leadership, and became profitable once divested. Every company they acquire, they seem to dissolve after a few years.
From an internal culture perspective, they are known for laying off their talented experienced employees who have been with the company for over 20 years in favor of younger, cheaper employees. In some departments, they have resorted to simply not promoting people and let people to leave on their own accord.
That being said, most of my experience in working with IBM has been while they were under CEO Ginni Rometty who led from 2012 to 2020. This was one of the biggest bull runs in history, yet the stock went from about $205 per share down to about $120 per share. They have a new CEO now, so things might change.
They do innovate, it's just that the places where they have been putting all their flashy marketing over the past couple of years have not been the places where they've been innovating.
They have not one but two custom CPU architectures designed entirely in-house (POWER and Z) which they've kept competitive over the years (in terms of hardware if not price). They're one of a very few entities (corporate or academic) at the very leading edge of quantum computing and one of the few builders of high-end supercomputers (#2 and #3 most powerful computers in the world at the moment are POWER systems)
The problem is that while they are legitimately extremely good at many things, those things make up a small fraction of the "surface area" of IBM and it's not what they have have historically been strategically emphasizing for the past couple decades. The average engineer's experience with IBM is more likely to involve their software products and consulting services and/or sales team than it is any of those things I mentioned.