That's like saying “The ‘Web’ can't display images, the ‘Web’ needs plug-ins to do so. Plug-ins like libjpeg or giflib”.

Right now, you can put a <video> or <audio> tag on a page and it will work in something like 95% of the browsers in use. That's already better than Flash and going up as IE8 users upgrade to newer versions of IE or install Chrome/Flash.

Sure, you can't rely on users not recompiling their browser to disable it but you also can't rely on 100% support for anything on the web – users disable image loading, plugins, stylesheets or JavaScript, install incredibly overzealous ad-blockers, use ISPs which tamper with page contents, etc.

Yup. Remember back when you actually needed helper applications to display certain image types?

https://www.as.cmu.edu/application/pref_1.gif

Or when GIF required a license to implement so people actually had to disable it until the Unisys patents expired. That was fun…