Don’t take the pills - the serving size on them is very misleading. You have to take a ton of them to have any effect. Gotta go with the powder.
Nothing wrong with supplementation! It’s hard to eat that much fiber (even if your diet is good) due to the relatively low fiber density of most foods. We adapted to our food sources, not so much the other way around, and when we did adapt our food sources to us we were not thinking of maximizing fiber content - and we don’t spend all day chewing on fibrous, foraged plants anymore. Plus, psyllium husk is a food. It’d be the same as eating a shitload of flax or something but with fewer calories.
For instance, raspberries are one of the most fiber dense foods at 8g fiber/100g of berries. You’d need to eat 568g to get your RDA of fiber. The avg person eats around 1.85kg of food daily - 30% of your diet by weight would need to be raspberries (one of the most fiber dense foods) to get enough fiber. Even moreso with other fiber-rich foods, like broccoli. You’d need 1.1kg of broccoli each day (8kg/week). The sheer bulk of that amount of food would be challenging for most people and just isn’t practical.