If your whole brand identity is built around being an affordable flagship, what did you think would happen if you're no longer affordable?
That being said, I had two oneplus phones way before they got expensive and they were awesome phones. Excellent battery life and specs, and super fast charging for their time. I'm sad to see them go but it was evident they were heading that way from Oneplus 8 onwards. The OP8 cost more than double the price of the OP1, just 6 years later.