I had the same reasons as you have, though in my case, it was a disillusionment due to solving the same problems over and over again, with the solid knowledge that the kind of problems asked of me would be very similar in future too. I started with a bachelor's, and stayed in the industry working at one of the large behemoths for 10 years.
When I realised that I am getting disillusioned, I took my masters via one of the universities offering remote campus, which gave me some confidence that I actually liked what I was planning to do. Once my masters was complete, I resigned, and got into a university for my Ph.D. in my chosen field. I am on my third year now, to hopefully finish in another three. I hope to either join a research institution or stay with academics as a professor after completion.
What I can offer you advice is that, be sure of what you want, and where you want it. Life in gradschool is very different from life in the industry, with different demands. I particularly feel that a Ph.D. feels like working in a startup, with you on the look out for opportunities, and once realized, having to move very fast to do the research before it is taken up by others.