Nikolas, to make a long story short, at the end of the day, you'll need high-trajectory irons.
You'll eventually reach Legend, TL, Champion and TC tiers, and have to deal with hard-rock "icy" surface greens where it would be virtually impossible to control and make your ball stop rolling unless with high-trajectory irons (+ advanced balls with high spin attributes).
The game (like all others) is designed to make you invest for better equipment and ultimately... spend money on them so it's obvious that it has to be that way..