I think one overlooked point is how many calories you are eating. Someone eating only 2500 calories in a day (maybe they're on a diet or something), eating 6 meals a day is only 400 ish calories a meal. That's a very small meal, and I wouldn't fell all that full after eating what basically amounts to a 10 oz chicken breast and broccoli. However, if someones eating 4000 calories than 6 meals would be just under 700 calories. Easily a "full" meal.
Basically, I think it matters how many calories you eat in a day. And personal preference, time constraints, etc. In a perfect world, when I'm eating to gain weight 4 meals and a small pre-workout shake is my "ideal" but I only consume around 3000 calories. Due to time constraints it's sometimes easier to just combine the last two meals in a day and really feel like I'm "splurging" with a 1300 calorie meal. Nice mentally.