I realise this won't be popular...
... but in some cases, IT are partially to blame. I work in the 'business' side of the organisation (in a government department), but I also understand IT more than your average civilian (particularly on the security side of things). In my experience, sometimes the reason business units do IT procurement "behind IT's back" or run off to cloud-based services is because IT are an unreasonable and inexplicable impediment. This might be unique to government, but I've come across a few IT areas now that manage risk by simply saying 'no' to every request. Unless, of course, it comes from someone in senior management. Then they seem to jump right to it, regardless of how insane it is.
Also, some functions that really should be managed by competent IT folks are instead managed by (as far as I can tell) non-IT folks. Usually 'content management' teams that, for whatever reason, are situated in the IT organisational group. Consequently, regular civilians end up assuming that when IT says 'no' they're just being unreasonable (even in cases when there's a good reason) or that IT simply doesn't know what the f*** it's doing (thanks to previous experiences with 'IT, but not really' content management teams). Examples:
1. I was working on a small project (1 man army) where I needed to write some stuff in python (mostly web scraping and writing custom parsers for weirdly structured HTML). It took me a month to convince IT to install a python interpreter on my machine. Tried to install a library: nope, read-only access to the directory. Over the next couple of weeks tried to convince IT that it was kinda pointless to have a python interpreter installed without being able to install libraries, but they wouldn't have a bar of it. Yes, technically I could have used urllib and regexps. That is, if I wanted the project to take 10 times as long to do. Eventually I had to give up and work from home (partially in my own time).
2. I use a *gasp* cloud-based service for making flow charts (lucidchart). Or I used to. When I tried to access the site from my current workplace I was confronted by the all-too-familiar 'blocked page', courtesy of our wonderful content blocking system (which seems to run on a whitelist basis, and MITMs using a custom CA cert that's that's dangerously insecure thanks to its outdated fingerprint hashing algo, but that's another story). I put in a request for it to be unblocked: nope, cloud-based services are not allowed here. When I ask why, am told it's an information security risk which, in fairness, is a legit issue in government. Everyone who works in my department has a security clearance, and has gone through countless security training courses, why can't they be trusted to not upload sensitive data to some random server? What was the point of the training in the first place? Hasn't that horse already bolted, given we can send emails to external addresses? Actually, isn't that a risk we've always taken given we allow people to walk out of the building without having to endure a bag check and body cavity search? And weirdly, why are Azure and AWS unblocked if this is such an issue? Yes, technically I can use your crappy flow charting software on the "officially approved software" list. But I'd rather use something that doesn't massively hinder my productivity. More working from home for me...
3. My department 'uses' Sharepoint. Yes it's awful, but I have no control over that. And because IT's access control policies don't allow 'business users' to be given any site-level admin permissions, we have to go begging to one of the 'content management teams' if we want to create a new document library. Or a new calendar. Or a new anything... These very simple requests can take 2-3 days to be fulfilled. I'm guessing because the 'sharepoint content managers' don't have a clue what they're doing and go bother 'real IT' whenever one of these requests comes in. Might there be a more sane approach we could take? Apparently not, is the official answer from IT. Now I understand why Sharepoint is only used as a glorified network share drive... Don't even get me started about the time I needed to write some crappy little CLIENT-SIDE Sharepoint app...
And the list goes on. The only good experiences I've had when dealing with IT were when I've been able to figure out where the knowledgeable folks are hiding (tip: they're usually in the 'IT infrastructure' teams, where you actually need to know what you're doing or the lights go out). Maybe none of this applies to any of you highly skilled IT folks. And I don't doubt that 90 percent of the time the problem is the 'business side' not having a clue. But a little introspection probably wouldn't hurt either.