- desperately needs a new self-propelled howitzer, as the M109 is a 60-year-old design that has been upgraded to its limit, and can no longer perform adequately in a modern near-peer engagement

- the AIM-120 AMRAAM is outclassed by other beyond visual range air-to-air missiles developed in the last 30 years

- the OH-58 Kiowa, based on the Bell JetRanger, was the Army's scout helicopter for decades -- but was retired in 2020 without a replacement

- the Ticonderoga-class cruiser, which was the first incarnation of the Aegis anti-air and anti-ballistic-missile system, is being retired without a replacement, forty years after it entered service -- its planned replacement, CG(X), was cancelled, and so more Arleigh-Burke class destroyers with larger Mark-41 VLS cells are being shoehorned in

- the Arleigh-Burke class destroyer, which also has the Aegis system, is still in production after 34 years because the Zumwalt-class that would've replaced it was a total flop due -- its eight-inch Advanced Gun System requiring bespoke ammunition on the order of $800,000 per round

These are all replacement programs that could have been (and in some cases were) started over a decade ago, but we are just now seeing the fruits of some of the very long development processes.

- the ERCA (Extended-Range Cannon Artillery) is not forecasted to enter service until 2025

- the AIM-260 is meant to enter production this year

- there is currently an ongoing competition between Sikorsky and Boeing to build the Army's next scout helicopter

- the DDG(X) program will replace both ship classes eventually, but is not even meant to begin construction until 2028

Meanwhile, one shining example of the successful replacements of older programs is the Virginia-class submarine. It remains one of the few examples of American military procurement that was delivered ahead of schedule and under budget, while still being a success.

Isn't that why we should invest in hypersonic missiles? It is a relatively cheap unmanned alternative to building aircraft carriers (and the obligatory fighters), and other large vulnerable systems.

That's not always true. Numbers can matter but certain technological leaps render whole classes of weapon systems obsolete.