I think maybe the point they're trying to make is that comparing a software development project that may include a number of unknowns to buying a pair of jeans where there are probably very few if any unknowns is fallacious and a waste of time.
That said, I don't think it's black and white. Some projects, making a simple web site that follows whatever Squarespace template is popular and filling it with some relevant content can be a pretty simple project, even to the point where the buying a pair of jeans comparison makes more sense.
The problem, I suppose, is when you believe strongly that every project can be accurately priced up front. Not every project is a moonshot, but some truly are and it's not always obvious up front which ones are.
And every engineer likes to pretend that their project is a moonshot.
If you are inventing something incredible,why are you someone's employee instead of getting capital investment or self-financing from your last achievements?
"Sweet, easy enough, I'll just use X, Y and Z, no problem."
"Oh but sorry you have to use A, B, and C instead. Oh and it'll need to connect to D for reporting, and we'd like it to sync with E which we've never done but they have an API so it can't be too hard, right? Oh and it needs to fit this design we've already approved that's about as far from native to the platform you're developing for as it could be and has a ton of UX issues that require fundamental changes to fix, which you'll uncover as you work. That's about as easy, right?"
"...."
[EDIT] oh and also one "minor" feature we're going to toss in later is actually big enough to build an entire company around so you'll have to waste a bunch of time talking us down from that while we quietly lower our opinion of you, and we've accidentally described a few things which are basically impossible by egregiously violating e.g. CAP theorem or being what's effectively a highly-available distributed filesystem that needs to fit without our timeframe and budget, which is 1/20 what it would take to maybe build that and that alone.
That said, I don't think it's black and white. Some projects, making a simple web site that follows whatever Squarespace template is popular and filling it with some relevant content can be a pretty simple project, even to the point where the buying a pair of jeans comparison makes more sense.
The problem, I suppose, is when you believe strongly that every project can be accurately priced up front. Not every project is a moonshot, but some truly are and it's not always obvious up front which ones are.