MiG-21 is not designed as a dog fighter. It’s a point defence interceptor designed to blast incoming bombing formations. It just happens to have certain factors that contribute to decent performance.

F-4 dominated over MiG-21 in Israeli-Arab Wars. This included MiG-21s flown by Soviet pilots.

F-16A dominated MiG-21s in Lebanon (even though Syrians claim otherwise but their claims are completely unconfirmed).

Nearly all were WVR combat – early Israeli F-16s were not BVR capable.

Once US got its act together, it’s F-4s were a match for MiG-21. In fact North Vietnamese also got great mileage out of MiG-17.

But an upgraded Mig-21 with TVC and newer avionics, it would be certainly a big diffrence.

TVC? We’re approaching realms of fantasy here. What next – F-86 Sabre could be an F-15 killer if fitted with AESA and AMRAAMS?

No-one is lining up to shove up a TVC on a MiG-21.

There’s also things like aerodynamics and structural integrity to take into account. Just cause you have TVC doesn’t mean you’re airframe is set up to do TVC maneouvring.

Best MiG-21 can get is MiG-21 Bison and from memory MiG-21bis isn’t as nimble as some of the earlier models but I could be wrong.

Interesting stuff PLA-MKIII.

Most of the MiG-21s were delivered to Warsaw Pact users by late 1970s. This did include ex-Soviet aircraft.

The retirement of MiG-23 instead of MiG-21 came after Berlin Wall fell and these airforces entered a quick death spiral.

The MiG-23 was not particularly more useful or effective than the MiG-21s.

Surely a MiG-23MLA/MLD would be more useful than a MiG-21MF/Bis, let alone a MiG-21PF/PFM.

True but the overall export numbers are rather limited and the overall earning are modest, at best. China has focused on emerging markets, that means countries with very limited budget potential. The only two considerable sales thus far are PAF order for JF-17 (so far 50) and EAF order for K-8E (80+40 units)

K-8s sells as well or better than any other advanced trainer aircraft (PC-21, MB-339, Bae Hawk, M-346, Yak-130, T-50) seldom sell more than 24 units.

In fact only Bae Hawk is continuing to sell in reasonable numbers thanks to Indian contract.

K-8s appeal is probably greater than most of the above list due to it being cheaper to acquire and operate and it’s got less export restrictions.

JF-17 is an export failure though.