The distinction between null alt text and missing alt text is something most developers get wrong - and it's exactly what ADA demand letters exploit. Automated scanners flag images with no alt attribute instantly because the screen reader falls back to reading the filename, which is the violation. Empty alt on decorative images is intentional and correct but looks identical to a beginner who's just skipping it.
The scale problem is worth adding to this - the nuance you've described here works perfectly for a developer building one site carefully. Where it breaks down is agencies delivering 10-15 client sites per year with 200+ images each. At that volume, writing contextually accurate, punctuated, properly categorized alt text manually becomes the bottleneck that gets skipped entirely. That's where most of the real-world ADA exposure actually lives.
Really solid article - the SVG accessibility section especially, that's rarely covered this clearly."