Final answer:
The development of play into expensive and complex forms by commercial firms involves the commercialization of art and theme parks, driven by the desire for profit.
Step-by-step explanation:
The development of play into expensive and complex forms by commercial firms that require people to pay fees in order to participate is a phenomenon that can be observed in various domains.
One example is the commercialization of art, where galleries and museums charge admission fees to view exhibits.
Another example is in the entertainment industry, where companies create elaborate theme parks or immersive experiences and charge entrance fees. This trend is driven by the desire for profit and the recognition that people are willing to pay for unique and immersive experiences.