[mooreds]

Can you see a light at the end of the tunnel? Does the business side of the business understand how much technical debt has arisen? Is there a third party solution that does 90% of what you need? Does the business need to keep upgrading the app or can it end of life it? Are there subsystems you can upgrade relatively easily that will have business benefit?

"Where there is muck, there is brass."

I would get all your concerns on the table with the person who writes checks and present some alternatives and let them choose.

(I went through this a few years ago with a 11 year old java + gwt webapp and had some success.)