Poll. Does everyone step on the ERP rake

I apologize in advance for a short and not very useful topic, but the time has come to dot the I.
At the moment I am working in a project for integrating a well-known and mega-expensive ERP system into the current information landscape of an enterprise. In addition to the tight deadlines, the lack of competent consultants, and as a result of high-quality documentation and a general vision of the system, we have a number of serious difficulties.
The main problem is that the time when the contractor with a beautiful smile told how remarkably fit all our processes into their system has passed. Now there is a fierce struggle for a place under the sun, namely, who should do the automation, what is not in their systems. Serious battles begin for the purchase of new modules that were not budgeted for, but without which we would be very ill.
One of the reasons for such a collapse was that there was no expert on these systems on the part of the company who, at the initial stage of the project, could bring down from heaven to earth stunned by the great capabilities of the user system and say his fe to some promises of the contractor.
If anyone had a major project for the implementation of the ERP system, I ask you to answer a few questions under the cat.