jQuery still exists. IMO, the ecosystem has just moved towards rich-client front end applications. There was no good tool/framework for that and people started

jQuery still exists. IMO, the ecosystem has just moved towards rich-client front end applications. There was no good tool/framework for that and people started fulfilling that need. Of course you could write like you said "unoptimized (or just plain horrible) code" which in an actual application is huge price to pay. I think it all boils down to being able to use the right tool for the job. I wouldn't advise using React or Angular to show static content e.g an splash page.