Seriously? You are telling me that Apple and Samsung both have an affordable price? Both are like at least 200(put your currency here) more expensive than the 9 Pro.
Better specs? Apple sticking to it's 60Hz refresh rate screen or missing out the charger completely is a better offer than OP with it's 1-120Hz screen and a 65 Watt charger, which they are improving on a daily base?
You are saying that Oneplus went downhill because they (finally?) tried to increase their camera quality, because their photos were like 5% more blurry than the competitors cameras before? And they just started to put more work into it?
Also keep in mind Oneplus sold only phones yet while Apple and Samsung have a variety of products in their portfolio and are existing much longer already, Oneplus made it's name so far.