I understand the sentiment, and disagree on a few points... if you're doing more adhoc enhancements using jquery, lodash or some chart/graph library... there's

I understand the sentiment, and disagree on a few points... if you're doing more adhoc enhancements using jquery, lodash or some chart/graph library... there's a decent chance that there's caching/reuse in play. If you're building a specific application, then I'm less likely to rely on a CDN... I think applications should largely deliver all of their own resources. If you're in financial or security (military) applications, there may be legal, resource and other requirements that supercede what you can do. It's not a one size fits all... that said, modern web application development centers around resources via npm, and largely delivered in your appliation bundle, so it's less of a concern in the common case these days imho.