They had two years to get ready for 64-bit only, though the writing was on the wall for more than 5. They didn't. Either they didn't care, didn't find it worthwhile, or they didn't even exist anymore.
Tell them what? Those developers already know that Apple is known for removing support for aging technologies way ahead of the curve. They also know that being willing to move fast and break backwards compatibility is what makes Apple, Apple. It's a major point of the article:
>There’s a whole book to be written about the “deal” a company makes to [...] promise compatibility. The reward of success is extremely high, but it is almost a Faustian bargain because you will absolutely cede the right to innovate
No one said that there weren't downsides to Apple's approach. The downsides are well known. And, as a user I'm slightly annoyed about the loss of 32-bit support. But if 32 bit support and backward compatibility is important, there's plenty of options including Windows, Linux or dual-booting MacOS versions [0].
Personally, I'm willing to suffer the short term pain of lost backward compatibility because I'm excited about the future of computing. As a user and developer I've already lived through 16->32->64 bit transitions (and similar disruptions). They suck at the time, but they're ultimately worth it. You can't stop progress.
