Late stage yes. But design has created the most valuable and profitable products and companies in the world.

Apple Ferrari Google Porsche Smaller companies like Yeti or Braun Etc etc

Once they use design to achieve dominance yes they do the rent seeking you are talking about.

Monopoly profits are the allure of innovation. Its the same reason those life-saving medicines get developed (patents).

Why is this a bad thing? Personally Id rather have an Apple monopoly than MSFT for instance. I really love using my Apple products. I never enjoyed using a single MSFT product.