Well with todays technology you can adjust images with great ease with Lightroom, Aperture, Camera Raw, Photoshop ect. Shooting film is one thing. The OPs original question dealt with digital images and probably RAW files. It is a horse of a different color. Investing in an expensive spot meter would be a total waste unless shooting MF and doing it all in house including making print. There is far little leeway in a wet darkroom.
So you think it wasn't Picasso it was the people that made his brushes, canvas and paints. The argument doesn't hold up with all the avenues avaliable to the modern artist of today. A camera is just at tool and just like hammers. Their is one suited for the job at hand.
Get a copy of Lightroom. Probably close to the same price as a really good meter.