I see high-fiber diets getting recommended a lot on these subs. Why do fiber supplements provide so little?

I've been looking at increasing my fiber intake, but it seems like all of the supplements provide such a small portion of the recommended amount.For example, psyllium husk pills or metamucil come highly recommended, but the dosage is 3-5 pills and only provides ~1 gram of fiber (or 4% of the daily recommended amount). Anyone know why that is? That's slightly less than one carrot's worth of fiber.Is there any easy way to get the recommended amount? I am starting to think about alternating between lentils, beans, and split peas as a meat replacement for one meal per day (replacement since they can be calorie heavy at larger serving sizes), which could realistically get me 2/3 of the way to the recommended amount before other vegetables. Still in the research phase.