Developers have always been free to choose techniques. Search engines owe you, the developer, nothing. If Google et al can't scrape your content, they'll scrape a competitor who better serves parse-able content. If you want to play ball with a particular search engine, you have to serve content that they can parse at the time.

But it's not just google now. It's anybody who does any kind of crawling on the web, which includes social media robots (that acquire images from the link), personal web crawlers, private internal search engine, data mining, even advertisement bots that check content. Would they all have to embed and maintain/update a JS VM?