A semi-informed decision is better than just believing the salespeople. Most software/systems in the magic quadrant aren't bad choices.
I think the siblings post (Gartner exists to gobble up money from incompetence) is closer to home. A semi-informed decision really isn't better. I'm not saying that making your decisions based on marketing hype is a good idea, by any stretch (which is what salespeople and marketing people will base their decision on usually). But outside consultants are really dangerous because they are targets (if not willing participants) in orchestrated attacks against your company. At best they will be trying to extract hundreds of thousands of dollars from you. At worst they will be trying to sink you deliberately. If you go with your salespeople's recommendation, the worst you will get is a bad ERP, WMS, or HR management system. A management consultant can cripple your operations if you follow their advice blindly.
You may think that hard to believe, but I've lived through it enough times to be doubly cautious.
Some might describe Gartner as a company that dispenses reasonable advice on demand to companies who need guidance on subjects well outside their core competencies. This is very much making money from incompetence, but it's the sort of profiting from incompetence that every expert adviser does.
As for the thread at hand, I second the answer that Gartner exists to provide executives a backstop of something goes wrong. People dont often get fired for buying something in the magic quadrant.
Why hire a strategic analyst with executive experience for 5 years if all they are going to tell you is 5% more than a Gartner consultant can offer you for 1/10th the annual salary?
To use your analogy, why should this hypothetical retailer hire an in-house team if they can get everything they need from another party for cheaper, with a small opportunity cost? And why is knowing which detergent to purchase making you any less reliant on the comparative specialisation of the supermarket?
Being able to talk to someone with some clue and have access to generally well thought out papers is useful. If you’re an SME in an area, they may give you additional perspective.
If you just read the Magic Quadrant for Business Process outsourcing or whatever and just call the top one, you are dumb. Conversely, if you’re going to be making a purchase in the space, and have never heard of 2/5 vendors on the top right, you may be missing something.
Not to derail your points; but their trends publication included a framework that is no longer supported. It could’ve taken an intern one minute to update.
Their trends seem dated because they're not going to feed enterprises bleeding edge tech trends; they're going to go with trends that are mostly proven, so yes at that point they're probably going to be a bit stale. Large enterprises with minimal tech advocacy/leadership in the senior leadership team eat this stuff up because they don't know much better.
Frankly, if your business is struggling with operations to a point where they are bringing in third parties to get told to outsource operations, I feel like your business has a competency problem that you can't place squarely on the shoulders of Gartner.