With all respect - the opposite is true. The web succeeded because HTML and HTTP are easy standards easily writable by humans with text editors. HTML was writable by non-programmers.
But then, I've always preferred strongly typed over stringly typed.
The reason HTML and markdown are more widely adopted than latex is because the former are more forgiving.
Once there was a standardized interpretation for malformed html, there was a chance that we could have treated that as a transparent conversion layer to xhtml. That isn't how WHATWG went, however.
But I don’t think the ambiguous html parsing made it easier. If anything it made it more difficult since you had to test in multiple browsers. Eg a table which was not properly closed would render in IE but not render in Netscape.