What will happen when most of the coins are in the hands of those companies? Right, the price of bitcoin, or more strictly, its purchasing power will skyrocket, so the companies will have a huge incentive to spend it.
I'd say the exact opposite. As they observe their asset skyrocket in the long-term, they're discouraged to spend it, because they can accumulate more purchasing power in the future if they do. This is the problem with deflationary currencies. You're not incentivized to spend them, but rather keep them safe or as we've modernized it, to HODL them. Although, this slow downs the economy.
The other problem with this statement is that we have no statistics to prove it or reject it.
And why should you prove this statement? Do you have to convince someone with strong inferences? Isn't it obvious for everybody you're talking that observing a 10x within a year means we had more investors?