While the MSRP for the i9-10900 (without or with the F) is lower then the i9-10850K/i9-10900K/KF, I have NEVER seen the i9-10900 selling, at retail, for less then i9-10900K. It has almost always been $50US higher (and a very similar story can be told for the i9-9900 vs the i9-9900K).
I would be very interested in a direct test of the i9-10900 against both the i9-10900K/i9-10850K. Basically power consumption stress test 100% on all 20 threads. As the non-K parts have a purported 65W TDP while we already know that the K parts have a 125W TDP but in reality act as 250W parts (at maximum loads but without OC) ...
https://www.tomshardware.com/reviews/intel-core-i9-10900k-cpu-review/2
"Intel set its official new PL2 watermark at a 250W TDP, which is double the 125W PL1 rating, and recommends that motherboard makers keep boost activity limited to 56 second bursts (Tau)." ...
During those tests, we recorded up to 332W of power consumption when paired with either the Corsair H115i 280mm AIO watercooler or a Noctua NH-D15S air cooler. Yes, that's with the processor configured at stock settings. "
In other words. do the non-K parts approach 250W or something closer to 125W (i. e. both max out at ~2X their listed TDP with no OC on the K parts)?
Oh and if such a test were ever conducted, please do so on a non-OC board (e. g. any LGA1200 like B460, H470 or H410). Thermals, power and speeds.