The primary issue with anodizing is that you cannot use secondary (recycled) aluminum billets. This means that every piece of anodized aluminum is extruded from primary aluminum billet (new raw material). One of the key benefits of aluminum is that it is infinitely recyclable. Anodizing it kind of defeats this purpose.
Alternative to anodized? Powder Coating. Powder coating is available with hundreds of color variants including anodic colors, designed to look like anodized aluminum.
Painted aluminum has a guaranteed long-term resistance to weathering and unlike an anodized finish, it can be restored on-site, quickly and easily without having to replace the profile.