Largest Publicly Traded Companies Prediction?

If we had to make an educated guess about which two companies are likely to be the largest by market cap in the future (or at least given all reasonable assumptions very likely to be up there) personally I believe it will be Google and Amazon.

And of course this post is not meant to be seen as something I am very sure about.

Google: Seems to be doing some fascinating things in AI. They have multiple self contained teams fully focusing on AI such as DeepMind and Brain. When looking at Google it even seems that building better AI's has been a fundamental goal ever since the company was founded. Recent advances in speech recognition and other areas prove that Google is at the very forefront of this technology and given its multifaceted approach to development it is likely Google will be able to found many uses for their AI tech.

Amazon: On the other hand look like they are increasingly winning the global battle for retail, IT infrastructure and increasingly consumer electronics (Alexa, Kindle, Fire TV). These markets are gigantic and if Amazon really does cement a dominant and lasting lead in 2 of 3, areas mentioned above, then surely it will continue to grow into the future.

What do you guys think? Do you agree?

Or do you think it is likely going to be a different company that does not currently exist?

Or perhaps something space related such as Spacex or Blue origin?

Or perhaps Alibaba and Tencent instead as they fill similar roles in China.

Or perhaps more likely that is could be another smaller company that will grow rapidly going forward?