Earlier today I read Lyn Alden's article about how market caps and the price of an asset is set: (https://www.lynalden.com/market-capitalization/)
The tl;dr for the article, is that for a one trillion dollar asset to go to two trillion dollars, and by extension DOUBLE in price, an additional one trillion dollars of fiat does not need to flow in. It is possible that only 10B of fiat could flow in, and the price and market cap of Bitcoin could potentially double. The only thing that matters is the price that people are willing to sell, and the price which people are willing to buy.
What is going to take us to $100k+ in 2020 is likely to be a sharp move upwards, instead of a slow crawl like we have been experiencing.
How you might ask?
Suppose a traditional mega-corporation like Wal-Mart, a sovereign wealth fund, or a central bank in came out and announced that they now had a Bitcoin position. Almost immediately we would see a massive price appreciation which could be upwards of 100%.
Why is this? Well, within a few hours of the news, HODLers, would be instantly validated, feel like the Bitcoin prophecy is coming true, and would be unwilling to sell my own bitcoin for anything less than $100k/coin.
Meanwhile, buyers, sensing that they are late to the party, and also feeling safer about taking a larger position now that X has purchased, would start to fomo in, and the notion they held just hours before of "$50k is too expensive" would be replaced by "$100K is a good price!"
I know this sub talks about it alot, but you can view this as another reason why it is critically important to HODL your Bitcoin, and not trade in and out of it. The price appreciation will come sharply, and seemingly out of nowhere. You do not want to be in the middle of trading shitcoins when this white swan event inevitably happens.