Yeah, but so does every US-based consulting outfit I've ever seen... IBM, Oracle, Accenture. The knowledgable Senior Dev answering your questions during the bid goes away _quickly_ once you sign. They're off to convince the next sucker...
But then the price mysteriously increases to the point where you might as well have hired them on-shore and you're not saving any money.
So, do you want to save money by offshoring everything, or do you want to get good people to actually do the real work that needs to be done?
They got where they are by doing what they are doing. Spending years on your project is something else.
I don't need to drag the building architects, master masons or master carpenters to help frame every wall of the house; ditto for code.