This is... false. For a number of reasons. Something can be economically rational at scale and still a gamble, because you do not have infinite funds. More importantly, past results are not indicative of future results in valuations. Thinking that a thing must increase in value because it increased in value previously is perhaps the dumbest fallacy in in finance possible.

Option 1: I offer you 99,999/100,000 chance to lose everything you have, And a 1/100,000 chance to get 100,001 times more. Expected value is net positive. And yet, you’d be pretty dumb to do it. Gambling.

Option 2: I offer you 9/10 chance to get 1.01x more. 1/10 chance to get 0x. Expected loss. Better than 50% odds of gain. Gambling.

Option 3: Coin toss. Triple your lifespan on heads. Die on tails. Definitely gambling.