Unless anyone has any solid proof of sales (and I doubt they do), then why even try to discuss this? Besides, there are so many factors at work anyway. Yesterday's popular, sales-wise, may not be the same as today's popular. Back then, video games were a past time that primarily children partook in. Children who often didn't have jobs, which means they often didn't have their own money, which is why trading was so common. Nowadays, I don't think the industry is sustained as exclusively by children. People who played video games back then are still playing them, and they're like 35 years-old now. The people who came after them are playing them, too, and that's a heck of a lot of people.
Point-being: More people are playing video games these days, and also more people who have the means to spend more money on them. I don't think you can really compare sales then to sales now without considering several different factors that have changed over the years.