I believe "creating anything useful" in this context means "doing any useful task"; I don't believe the original poster intended to put nurses, cops, or any service job in the same group as investment banker and ___domain squatter.
In that sense, investment banker is still a useful and necessary job, unlike ___domain squatter.
So in your opinion is a ___domain squatter worse, the same, or better than a real estate investor? That is someone who identifies something that has value that might be able to be sold at a higher value at a later date and buys it for less than they intend to sell at that later date?
IMO ___domain squatters are worse (and definitely more annoying). While real estate investing still seems like a parasitic activity and I'd be happy for it to disappear, at least when it comes to houses, a buyer usually doesn't care about a particular building - one can equally well live in a house next door, or next street. Whereas domains are almost never interchangable; if someone squats on my-company-name.com (and similar forms), I won't settle for company-my-name-friendshipismagic.com; I am pretty much forced to either buy from them or change the company/product name.
With respect to real estate investors provide liquidity as there is not always an end user who is willing to buy at the time you want to sell.
As far as "squatting on my company name" the majority of the vitriol on HN regarding ___domain names is not directed at "squatting on my company name" (to which there are clearly defined rules and procedures for recovering a ___domain (UDRP)) but just at the general idea of someone getting a ___domain and holding it to sell at a later date.
As far as "to either buy from them or change the company/product name" we are talking the year 2014 here. If you are starting a new company you should be taking into account whether the ___domain name you want is available. People don't, I know this for multiple reasons. One is that I get assignments to buy domains for startups that have already branded (which they shouldn't have done) and then come and say "I need this ___domain what can you do for me?" (in so many words).
Now if you are an established company and all the sudden woke up in 2014 and want your ___domain well then I guess that's to bad. Even back 10 years ago big corporations had this problem because the people they hired didn't know enough to lock up their domains. Either because they were inept or because they didn't feel it was important to have (so what can you say about that?)
In that sense, investment banker is still a useful and necessary job, unlike ___domain squatter.