Let us talk according to the topic, for those who were young in the 1980s and even 1970s, still can remember what was said in the west about MiG-29 and Su-27.
The Russians have never said MiG-23 is as capable as F-15, they said that the MiG-23 and F-15 are far behind MiG-29 and Su-27, and let us see it from design perspective, the F-15 flew in 1971 for the first time, the Su-27S was first flown in 1981, you are talking 10 years difference.
Today is similar J-20 flew 20 years after YF-22 and 14 from F-22, the MiG-23 flew in 1967, 3 years before F-15, there is a tendency in the west to overstimate Russian or non western fighters.
The Russians said the F-15 is closer to the MiG-23 in turning ability than to the MiG-29 or Su-27
Today no one knows how good are indeed J-20 or T-50 with respect F-22a
Weapons are in a race.
If you would compare F-104 versus MiG-21, you would see the MiG-21 was indeed very good, by 1970, the MiG-21, MiG-23 and MiG-25 surpassed F-4, that is the reason for F-15 and F-16.
F-15 surpassed MiG-25, that is the reason for MiG-31, MiG-29 and Su-27.
F-22 came and surpassed Su-27 and MiG-29, that is a fact, but Su-27 surpassed F-15.
Today J-10 is indeed more capable than F-16 and MiG-29 to the level MiG-29 and F-16 without updates will struggle against J-10.
So Russia designed T-50 and china J-20 to surpass F-22.
Your logic is as F-15 beated MiG-29 or MiG-25, F-22 will beat J-20 or T-50.
However the Serb MiG-29s were in terrible maintainance shape, had no AWACS, the Iraqi MiG-29s also were relatively new to the Iraqi pilots and western sources do not acknowledge any kill claimed by Russian sources.
So it is simply you do not believe in Russian claims, i do not blame you, you are american, you support american claims, however it does not mean the Russians accept the american acount or we only have a single version of what happened.
So let me see mig, I'm so old, with your new fighter math equation you can predict how well any aircraft will do in a combat situation by its model designation. OK so see how I do with the mig 29 new math fighter predictor equation, [figured with the super duper fighter equation predictor ring], sold only in 20 oz boxes of cracker jacks in South LA on Wednesdays. OK, now F-15 is 3.1 times better than F-4, ok good so far, mig 23 is 1.5 times better than an F-15 and slightyly edges an F-22, and the mig25 is 1.71 times better and the Su-27 is almost 2 times better and the mig 31 is 2.07 times better than an F-15, so since that is so the J-20, J models are slightly better than F models which means the F-22 and the J-20 are approximate equals, [ How'm I doin so far? pretty good huh guys] and the T-50 is 2.5 times better than the J-20, and 2.6 times better than the F-22, unless it is block 2.0 and then its only .05 times better. I hope you guys like this, because I have stayed up the last three nights trying to calculate this on the russian fighter factor decoder toothbrush, where you have to count the red bristles and blue bristles and multiply that by 3.14. OK mig I give up, I will buy that last box of 20 oz, cracker jacks for 50 bucks, but the decoder ring better be in there!
Oh yeah an mig 31 will only win the weapon race if it is downhill, F-15 will win the weapon race uphill!