Not on the "modern web" you wouldn't, even the current speedy versions of V8 and ${whatever}monkey now used by Firefox the thing often is brought to a crawl by the deluge of Javascript. Imagine your current browser, only 100 times slower and 10 times more memory-hungry.
Nope, the solution lies in getting rid of most of the Javascript on most pages. uBlock and uMatrix can help a bit but the real solution lies with web developers. If and when that goal is achieved it would be possible to browse the web using a slow-but-'safe' browser. Some pages (e.g. SPAs) really depend on all that Javascript and as such won't be useable withour 'modern' JS engines but there is no reason for e.g. your bank or payment processor's pages to depend on near-native speed Javascript engines.