I worked at a bank in IT, and we called this "shadow IT". When departments and teams have budget but the organizational friction to do anything with it is too much, you end up with a lot of excel, access DBs and stuff built on sharepoint, notes, whatever is available. Life, uh, finds a way.

IT groups like to rail against this, but they are also the ones setting up architecture review boards, CAB's and things like new activity committees, where good ideas go to die.

It's called Shadow IT and it has plagued corporations for decades.

Ironically Excel is often the tool of choice, and it happened in an org I was in. A finance team had an Excel workbook they used to calculate payouts to different stakeholders of a set of oil properties. Over time this workbook grew bigger in scope and in data and was becoming unusable, so they came to our app dev org to rebuild it as a standalone application. In the process of rebuilding it, critical miscalculations and rounding errors were found in the workbook, and we owed years-old payments to some of the involved parties.

In a worst-case timeline, the team avoids having the problem solved by IT even longer, it culminates as a critical workflow issue (workbook becomes unusable to the point that the finance team cannot do their job at all and there is no quick solution), and the third parties realize they are owed money and sue.