[dusted]

You answered your own question:" The internal messes are always being built by people on a steady payroll."

The internal software is a direct money sink to a company, it is _VERY_ visible to the organization that they're pouring money into a product that's only tangential to making money. So internal software is allowed to be developed until the point where it becomes useful, but not more. You can argue how wise it is to use internal software, or to prioritize it in this way,but the incentive for not pouring more cash at it (wrong as it may be) is clear enough.

Disclaimer: Author of many awful internal tools.

[captaincaveman]

Agile or not software projects are normally .. projects, with an expected budget. Much of that budget gets 'used' figuring out what the point of the project is, requirements, managing the project deliver, stakeholder management and reporting, working with other teams to access, integrate and understand systems ... then the building of the system is built with what left, which leaves no room for your 'gold plating' ...

[Trex_Egg]

Also the means of the many internal tools that I've been using are mostly short sighted and built with minimal expenses.