My sense is Marco is looking at the money in terms of: "how much yearly income can my money generate, and what kind of lifestyle would that be?" (kind of like thinking about a retirement account). In that sense $10M in savings is not enough to start buying yachts and helicopters assuming he doesn't want to blow all the money at once like a stereotypical lottery winner.
More importantly, he makes it clear he'll never have any money worries if he's careful. That implies a decent amount of money, and I think that's what most people on Hacker News really wish they had.
Charles Simonyi would commute to the MS campus via helicopter and we all know about Paul Allen's yachts. I think it's more about it being similar to buying a second home or a nice car to normal people. I.e., you may or may not notice the expense, but it makes your life easier or more pleasant.
Are you implying that he is predisposed to blow it like a lottery winner given the fact that hasn't worked there for years and was really just the beneficiary of luck and inflated valuations?
I took the implication to be exactly the opposite of your line of thought. Given that his article is about all the work he put into Tumblr, I'd say he is not likely to have a "lottery winner" relationship with money.
More importantly, he makes it clear he'll never have any money worries if he's careful. That implies a decent amount of money, and I think that's what most people on Hacker News really wish they had.