Yes, it is a certified way of making money...apart from the hundred or so people who also do this. However, you might have noticed that there are many people who use their first skill on a build skill, rather than a job skill.
It might be risky, but for every person who goes bankrupt, theres always another who makes it big (mainly because some people always make it big, and they make up half of the "lets build a building" population).
It is these people that you see in the top ten wealth/networth , and not the other 90% of the population that get a job....put money in the bank....wait...wait even more...get fired....get another job....and then in the exitement forget to stock their home

why isn't there a sleeping emoticon?
Plus, you must realise that other people play this game too, and if you ripping 5s per month (50s every day) off someone, then the employer must be making quite a bit of money.
Also, most people have realised that having a high interest rate which means the bank makes more money than if people were making food and drinks and homes etc will mess up the economy more than a single player owning 90% of the money in the top ten wealth list (and this has actually happened,, although the economy wasn't messed up due to the player losing interest), with the result that the current islands shouldn't really have a high interest rate, unless the host has seriously miscalculated the amount of money a business can make...
Anyway, the point is, you can make more money from running your own business...with the added bonus its fun.
This post would had been a lot more witty and abusive towards all players, island owners, forum readers and cats, but the computer crashed, robbing me of spontaneousity