[MeganC]

It is quite obvious that the T-14 is a lemon or else Russia would have deployed it by now. Ditto with their Su-57.

[Renfrew]

One of the most important things we have learned from this war is that Putin’s much vaunted military modernization was an illusion.

Almost everything deployed to Ukraine has been of Soviet vintage.

The newer systems either don’t exist like the T-14 and Su-57 or have performed far below expectations like the S-400 that has failed to protect the Russians from air attacks.

[Rockingham]

Russia's arms industry has been a shambles ever since the fall of the USSR. Even when a technically superior new weapon is conceived of and announced, it often fails before a practical detailed design is achieved or prototypes produced. Serial production is rarely accomplished due to lack of funding, technical defects, industrial deficiencies, or because critical components are unavailable due to sanctions.

The T-14 has suffered from all of these problems and, whatever merits it might have in the abstract, there is little point in committing the handful that have been produced to combat in Ukraine. Most would soon be lost in combat and unavailable for the lengthy testing still needed to refine the design. The T-14 is still a long way -- if ever -- from production in useful numbers and is unlikely to see service against Ukraine.