There is really no cutting edge technology going on in eastern Ukraine right now, at least not at the base layer. It’s older tanks, older infantry carriers, older artillery. There have been upgrades to systems on those vehicles such as countermeasures and reactive armor, but buy large the systems are legacy.
So why in the world are think tanks across NATO using this as an excuse to pressure governments into the purchase of modern tanks and fighting vehicles? Well, never let a good crisis go to waste is the most accurate answer, but it cuts deeper than that.
The assumption is that the “new” tanks and fighting vehicles will be much like the F-35, you aren’t buying the plane so much as all the goodies that are being developed along with it. Next gen sensor fusion, next gen countermeasures, etc. The Armor community is very concerned about having vehicles that can take a hit from a main battle tank, or have vehicles that can resist modern AT weapons.
This is a valid assumption that newer can be better, but it costs a lot of money. And you end up with a system will generally be just as good as if you’d simply upgraded your legacy fleet. Sure a next gen fighting vehicle might be faster than a Bradley and might hold more dismounts, but fundamentally the Bradley could be upgunned to 30 or 40mm today, and the TOW pod armed with wireless missiles. The reactive armor of the survivability kit means that getting something more survivable than a Bradley means getting something also much heavier.
And there is the other assumption, that another round of procurement wars will produce some breakthrough technology that revolutionizes things. This is a bad assumption. The various ceramic substances that make up modern tank armor composites have been continually researched and improvements have stalled. For decades.
There are only so many elements on the periodic table, and the new ones being added aren’t very useful to materials science (half lives are way too short). The easy combinations have all been tried at this point, so research has to go to the uncommon combinations. And that is why there hasn’t been a breakthrough in vehicle armor since the 1970s. Simply throwing more money at the problem isn’t going to make more elements appear on the periodic table, and some new material won’t materialize out of thin air.
So purchasing a new tank or fighting vehicle means it will automatically come with 1970s era base armor. Even reactive armor. So replacing decent hulls with newer decent hulls for the cost of a new hull when you could just upgrade add-ons doesn’t seem smart. Of course there are people who assume that “newer” means “better” because for darn near everything else, it is.
What would be smartest is keep doing the upgrades on legacy platforms until a breakthrough in some technology occurs that can only be implemented by adopting a new generation of vehicles. Until then, it’s just not worth it to buy new hulls to do old jobs.
With aircraft it is a different story. Advances in engine design, stealthy construction, and even automated maintenance tracking have made it worthwhile to buy newer aircraft. However there are plenty of good reasons why the USAF still flies the B-52. I think it would be better in the long run to have Boeing convert some civilian passenger jets into a big bomber platform as a follow on successor to the BUFF, but that won’t happen because once again you’ll get something new that only replicates the capabilities of something old that has been upgraded over the years. In fact, there is talk again of getting an engine upgrade for the BUFFs still in service.
Sometimes things are cheaper to maintain than replace. Sometimes it’s the other way around. We really need to know when that crossover point is, and when to cut sling load on maintenance and upgrades, and when maintenance and upgrades make a lot of sense.