lowest price - lowest service
A number of years ago I was working at JPMorgan when they had outsourced their IT services to IBM, who had won the contract as the lowest bidder. However, the agreement included professional services billed separately from the core contract.
By the time I joined, the arrangement had been running for several years, and it was widely understood internally that almost any change was classified as professional services. The associated costs steadily accumulated and, over time, likely matched or even exceeded what some of the higher bidders would have charged in the first place.
As I understand it, JPMorgan eventually decided to terminate the remaining contract early and bring it all back-in-house (backsourcing). This may have not been the only reason because there was a merger at the time and I guess there probably were a few reasons.