Front-end and backend frameworks, like Rails and Angular, give structure to our code, dividing it into, smaller, easier to maintain chunks.All of these tools catch syntax mistakes earlier in the development process than what is typical for online validation.
Our framework is tested in almost every perceivable browser, and battle-tested daily by our 20-plus team of engineers and designers, and yet we still don't meet validation, even though it renders well in most every browser.
Editing software and IDE's now have linting — a method of validating syntax — built in, or have third party extensions that do the same.
Proper syntax highlighting in editors can quickly catch a missing div or quotation mark.
A web validator shouldn't be used as a debugging tool. The built-in developer tools in the browsers have gotten extremely sophisticated and will now notify you if there are any parse errors while processing your HTML, CSS or Java Script.
Validation is also frequently done against live code, which opens up other problems.
Can we satisfy standards compliance without the need for validation, or, alternatively, is there a better approach to validation? Validation was created, in part, to drum up interest for standards compliance after newfangled browsers like Netscape and Internet Explorer started extending the capabilities of HTML in the early 1990s. Many rebuffed these additions as going beyond the original intent of the language, to provide document structure, not influence stylistic choices.