Just because most of the free software ecosystem relies on unpaid volunteer work does not mean it is a desirable state of affairs, especially with billion dollar companies building on top of said work while hardly contributing anything back.
Both Espressif and Raspberry pi (pico) target OEMs who will buy millions of their chips. They've both embraced the hobbyist market as well, but it's not how they've recouped their investment.
Arduino targets the hobyist market where customers will buy one (or at best a handful) of their boards. Arduino simply has no other way of recouping their investment than selling expensive hardware.
So I don't think it's fair to say that Arduino is being greedy. Also FWIW, Espressif's official dev boards are also pretty expensive. Not Arduino expensive, but several times the price of identical "clones" based on the same reference design and using the same official esp32 module.
If you think the price is unreasonable, don't buy. You have listed what you seem to think are better options. I agree that there are better options. If somebody else wants to spend their money in different ways than I do, let them. If Arduino thinks they can make money this way, let them try. If it works, good for them, I guess. If it fails, I guess the joke will be on Qualcomm. Honestly, Arduino could slash their price to be $1 less than a Milk-V Duo and I'd still by the Duo. If the Arduino was $1 less than an ESP32, I'd still by the ESP32. So I'm not sure lowering prices wouldn't just hurt them.
I have never bought an Arduino. I have bought a few Picos, a few ESP32s, and a couple Picos. And a clone of an Arduino Nano integrated in a system with a Pico for 5V logic, specifically, to implement a PS/2 controller. I don't see any advantage an Arduino has over an ESP32, aside from 5V logic support.
While that is true, if Espressif and the Raspberry Pi Foundation can build their SDKs and still offer cheap chips/boards, so could Arduino.
I'm not expecting a $0 markup, but Arduino prices are simply unreasonable for what they offer, especially if you live in a lower income country.