I guarantee that its easier to graduate from plankton to minnow than any of the others, simply because the entry requirements for each category increase by a factor of 10, so it's exponential.
plankton - 0 vests
minnow - 1,000,000 vests
dolphin - 10,000,000 v
orca - 100,000,000 v
whale - 1,000,000,000 v
Yeah, its easier if you're an early adopter - but considering this will still be continuing in 5 years time, maybe more, we're early adopters which gives us a huge advantage.
I've stumbled upon a few accounts from two years ago which made one post, got $0.10 and gave up, but they don't realize their accounts have hundreds of steem power in them today thanks to that one post.
But you can self upvote and so higher you get up so more your self upvote counts. That too is exponential. Question is: which function rises faster? (I honestly don't know)
Another interesting aspect: And a new account has about 15 Steem Power donated by someone which equivalents to about 7000 VEST. With every Steem Power you gain the donations is automatically reduced. So you stay at 15 SP / 7000 VEST for a long time.
You have to actually rise the whole six digits from 0 to 1 million to become a minnow.
But yes, becoming a minnow is still doable. You need a little more about 540 steem power. Which is little more then a thousand dollar.
PS: I currently have a little more then 50 steem (power) and a little less then 50 Minds Token. It will be interesting to see how that will change over time.