That's why contemporary re-hashings like Scooby-Doo, Josie and the Pussycats, and Underdog were such big financial and critical hits? Live action retreads of old cartoons almost never work.
In this case, the problem isn't that the Wachowskis deviated from the source material, but because they didn't know better to cut out the parts of the source material that were pretty bad even back then, such as the one dimensional, cardboard cut-out characters. Who wants that? These days, even the simplest of characters deserve a bit of nuance.
Nostalgia goes a long way in drawing people in, but once they've had their filling, they'll start to realize the things that made the original so great is now outdated. What comes next is substance, and unfortunately Speed Racer just didn't deliver.
If the original Mach GoGoGo didn't exist, would this movie still be or have done any better? (Given this film would be a totally original property). Movies like Iron Man and Transformers would still stand strong as good movies if the original source had never existed, Speed Racer would not.
