When you buy a branded Arduino, you're supporting the people who develop the hardware, software, libraries, documentation and learning resources, community platforms, and educational outreach.
Ten years ago, I happily paid for an Arduino. I was interested in microcontrollers for about a decade at that point. Even though microcontrollers were inexpensive, I didn't get into them previously since I needed that extra support. Yet the Arduino development board and IDE provided that support in a form I found palatable at a price I could bear. (There were certainly alternatives that provided something similar, but they were expensive. There were certainly alternatives that were inexpensive, but they lacked support.)
Ten years later, the situation is different. More experience means that I don't need as much support. For the most part, I just want a development board that I can solder a header onto. It's something that I may be willing to pay $10 for, but it is much harder to justify at twice the price. It looks like this is something that the Raspberry Pi Foundation realized with the Pico. The development tools are better compared to those provided by a microcontroller vendor than with those provided by Arduino. The board's price is better compared to those of eastern companies than western ones.
The reality is that we need both. The reality is that western boards will probably be more expensive than eastern ones, but the price differential need not be so large when similar products are offered.
EDIT: clarification.
But if you succeed in offering an inexpensive good product, people will do things for you. Espressif did that and what people are doing with these modules and boards is amazing.
In some cases what you say is true, the cheap clone is piggybacking on the R&D of someone else. Yet the situation is definitely not so clearcut in the case of many development boards.
The heart of a development board is the MCU. Assuming a genuine component is being used, the software stack is typically provided by the vendor of the MCU. The supporting circuitry is either well known or provided in the vendor's datasheets. In the case of basic boards, there is not much R&D happening.
It is also worth noting that the software stack for many boards is open source. Let's ignore the compilers. They're typically based upon GCC, thus open source, but they are typically supported by the MCU vendor which is supported by MCU sales. Consider something like Arduino and MicroPython. Some board vendors undoubtedly invest in them, but it is open source. Others can use the products of their labours. Equally important, others can contribute to them. The board vendors who invest in the software also benefit from contributions.
On top of all of that, Chinese firms aren't the only ones making clones and Chinese firms do more than create clones. For example: I haven't heard anything about Espressif parts being clones of original brands.