This story isn't EXACTLY what occurred here but
I worked for a company who was faced with a big customer interested in a deal that would roughly quadruple the amount of business that we did, possibly more. But as things went on all the assurances / up front claims from big company had exceptions. "Well that's not always the case." and the complexity and frankly our trust in this big company seemed to erode fast. Yeah they said they'd pay for the extra work we'd have to do, but it wasn't clear (specifically to me) if even they understood how much work that would be and from meeting to meeting expectations seemed to shift, sometimes wildly on the part of big company. The more clarifications we asked the weirder things got. It would take a dedicated team larger than our own company to really even approach / get a handle on these guy's problems.
We passed. Told them they were too big for us and frankly we weren't setup to deal with them at their scale and potential complexity. We hoped to be one day but we just weren't there yet. They took the news well.
Another similarly small company got the deal... 2 years later went bankrupt. They invested heavily to support big company, lost many of their smaller customers who were their main income (we know because they came to us), and the deal with big company failed because big company really didn't know what they wanted and ultimately should have chosen a much larger software company.
Years later big company had a subsidiary that was largely independent but had some issues that our software could solve. Big company VP remembered us and told subsidiary "just hire those guys". So we got a deal in the end / handled the subsidiary's problems easily / quickly.