Does Deno will replace Spidermonkey JS engine in the future?

As I see, MozCo drop a lot of money on Deno, does it want to use Deno as their JS engine? In works of replacing old slow Spidermonkey with V8? Or just as commercial way to support Moz pool money as they bleeding from Firefox?

I am interested in this too.

What effect will Rust have on the JavaScript performance of the browser.

The only answer I have gotten so far is backwards compatibility concerns.

But I posted another similar question:

I hope somebody knowledgeable can answer these questions.

PS: As far as I know, Mozilla has nothing to do with Deno.

it drop some money on Deno Project, and attempt to make it profitable

I remember the portion of Mozilla Corp is bigger than the rest at the time of announcement, and I really hope they become so profitable that make DenoJS the new source of MozCo income.