A lot of the "system integration" work that these big consultancies get hired for is more like configuration (of big erp systems like SAP and Oracle or whatever)? There may be some overlap but as I understand it's very different from what many people would think of when they hear software development.
Edit: I think this causes internal confusion as well, like consultancies hear "software project" and assume their team can do it because they have "software" experience, and then you end up with these disasters like you hear about from Accenture and Deloitte where they spend 10's of millions of dollars building a website that doesn't work. The parallel language in a academic, SV type tech, and tech consulting is actually a source of a lot of confusion.
The thing with these consulting companies is they will never say no (including for stuff that they are wildly unprepared to do). You can hire them for installing software on employees' computers, deploying and managing some SaaS product, building a healthcare signup website for an entire state, building an internal portal, running a tech conference, even planning a company picnic (not kidding). So trying to define what area they operate in and what exact role their employees play is impossible.
Edit: I think this causes internal confusion as well, like consultancies hear "software project" and assume their team can do it because they have "software" experience, and then you end up with these disasters like you hear about from Accenture and Deloitte where they spend 10's of millions of dollars building a website that doesn't work. The parallel language in a academic, SV type tech, and tech consulting is actually a source of a lot of confusion.