This is oft-repeated, but doesn't stand up to any sort of logical scrutiny. You think there aren't dozens of parties with interests adverse to Intuit who could pony up $10 million to lobby for the opposite position? I think of this every time someone mentions lobbying by telecom or media companies: for what Facebook paid for WhatsApp, it could purchase all of the lobbying efforts of the top 10 D.C. lobbying firms for the next half-century. You think the Facebooks and Googles of the world are above buying legislation in business-critical areas like telecom policy or copyright if it were that cheap?
What lobbying does is help you tap into a base of support that already exists. In the case of Intuit, their lobbying dollars go to supporting Republicans and Libertarians who don't want to make filing taxes easy. The cost and burden of filing taxes is a major hammer people use to chip away at the whole concept of progressive taxation. It's a major selling point of proposals like the flat tax or consumption taxes. In a system with employer withholding, it's the only major reminder of how much the government is taking out of your paycheck each year.
That $10 million doesn't guarantee Intuit favorable legislation--it leverages a deep divide in the polity that happens to advance Intuit's specific interests. And at the end of the day, almost all effective lobbying, at least at the federal level, takes that shape.