Modern browser extensions are written in JavaScript, making them portable, verifiable, and easily sandboxed - not something you get with an executable binary bl

Modern browser extensions are written in JavaScript, making them portable, verifiable, and easily sandboxed - not something you get with an executable binary blob that until very recently ran in the same permission context as the local user - which on Win9x through XP meant root. Handily (and amusingly), Microsoft's Edge extension API is designed to be compatible with Chrome's - I understand there's a degree of mutual-intelligibility with Firefix too. And aggressive caching just makes sense - consider people today with 10+ Chrome Windows open, all with 50+ tabs each - not even 10 years ago IE6 still ruled supreme - with one document per window. And even then machines had similar orders-of-magnitude of RAM as they do today - my 2006 rig had 4GB of RAM (XPx64) my current machine has 4 times that.