some people get quickly bored no matter what kind of job you throw at them. IT is currently too geenerous profession and these spoilings are very common these days. good if you have skillset interesting enough for companies to overlook that (nobody is blind nor stupid enough to not notice that at all). or if you can just sell yourself, it doesn't matter how one gets the job. but for anybody looking for more than short term head count increase, with at least a bit of project management experience, what you describe is simple - a big NO, not worth the hassle. If last 10 comapnies failed to retain you for more than a year, 11th won't be much better, would it...

if you are a true born hopper there is perfect way to do things right - self employed consultancy. it's also paid better most of the time.

and btw getting bored too quickly is terrible, terrible personality trait, for any aspect of life.