A critical challenge for the military is maintaining aging equipment when original suppliers no longer exist. Advanced, flexible factories can reverse-engineer and produce these 'obsolete parts' on demand, solving a critical maintenance bottleneck for in-service submarines and other legacy systems.

Because AT&T owned and rented every phone, they engineered them for extreme longevity and easy repair to minimize their own replacement and service costs. This business model, not just good design, was the key to the phone's legendary robustness.

The recent controversy isn't about access to physical parts, which the company has long provided. It's a modern, digital-age problem centered on farmers' desire to update and manage the software on their equipment's microcontrollers themselves, forcing the company to adapt its service model.

Instead of focusing only on new technology, it's crucial to see how old technologies disrupt industries in new ways. Mala Gaonkar cites lithium-ion batteries, invented in 1976, revolutionizing the modern auto industry, and gaming GPUs from the past now powering the AI boom.

Companies like Apple and John Deere embed software that rejects non-proprietary replacement parts. This tactic, called "parts pairing," destroys interoperability and forces consumers to buy expensive, manufacturer-approved components, locking them into a closed ecosystem.

Charles Brannock's device dominated its market for a century not through constant updates, but by being a fundamentally perfect solution from the start. This "category killer" status made it the undisputed gold standard, rendering competitors irrelevant and long-lasting.

While modern UIs are essential, the backend IBM i (AS/400) platform remains entrenched in many businesses. The reason is its extreme reliability and stability, which would require massive, difficult, and expensive custom software development to achieve on open systems like Linux.

Having experienced the pain of supporting equipment in the field, one engineer designs with the primary goal of making systems so robust and intuitive that he will never be called to fix them. This "don't call me" mindset is a powerful driver for true design for serviceability.

The designer of the iconic 500 series phone, Henry Dreyfus, believed in eliminating friction between user and tool. He applied this to his business by refusing speculative work and design contests, insisting instead on direct collaboration with engineers.