Small is beautiful
Software project is hard but huge firms do not have better success rate than smaller firms. The inverse is true. There are plenty of evidence of disastrous software projects performed by the big 4.
Hertz is suing for the $32m it paid Accenture in fees to get to that aborted stage, and it wants more millions to cover the cost of fixing the mess. "Accenture never delivered a functional website or mobile app," Hertz claimed.
If you want to get something innovative done, go small.