I don't think editing software makes you lazy. I can't the same about digital cameras, but that's a different topic (even if it has been touched on here).
For former film photographers, the effect of knowing that there is a "software safety net" probably depends on whether they used colour or black and white. With slides there was little you could do after the exposure; with colour prints - well, very few amateurs probably made their own. Black and white photographers were accustomed to using a darkroom, knew what they could achieve, and in some cases persevered until they got the print they wanted. Hence, they used the darkroom in the same way as digitalographers use Photoshop (or whatever) and saw it as an integral part of the image making process.
One of Edward Weston's sons complained that when assisting his father in the darkroom, Edward would sometime take 3 days just to get one print the way he wanted. Anyone spent three days in Photoshop on a single image? Whatever your answer, lazyness doesn't seem to really enter in. Photo manipulation has always gone on; and the skilled photographers usually took into account what they were going to do afterwards.