[jlcummings]

The B52 first was first rolled out for production use on 18 March 1954. The "...long-rifle of the air age..." -- Nathan Twining. It has not been manufactured since 1962. They are still in active military service, the ones that remain, and continue to see upgrades and evolving mission scope. 100 years of service is feasible.

Cost per flying hour of a modern B52: $70,000 [1]

1. https://www.airforcemag.com/article/re-engining-the-b-52/

[gsnedders]

They also spend comparatively little time in the air. Compared with passenger aircraft where their return-on-investment strongly incentivises them being airborne as much as possible, military aircraft spend _a lot_ of time sitting around, either unused or in maintenance.

[imtringued]

It's very easy to upgrade a strategic bomber. All strategic bombers are prone to interception so the only way to stand out is by having a bigger and modern payload. You can see the same development with tank cannons. Bigger calibers aren't necessary. The Rheinmetall 120mm cannon can be upgraded by simply shooting modern munition.