Security updates last at least a year and a half for every release and the Support Center supports its customer on any Linux Mint releases and with any linux related questions they might have (mint-specific or not).
As for the future, 2 years is a lot of time and I hope we'll be as vibrant as we are now with a much wider user-base and a group of companies as well. We'll be focusing on two aspects: innovation (as we're doing now with cutting edge technology and fast cycle new developments) and business (with a pro edition and better solutions for companies to switch to Mint on their desktops). We want to become the number one choice for the desktop. I believe we can achieve that both at home and in the company. Our strongest (and also weakest) concurrent is Microsoft Windows, and looking at its market share I am pretty sure we are going to grow.
Will Windows be much different in 2 years? Will it be the same? Are we in a positition today to compete against it? Will we in 2 years? The future is bright and I'm really confident about it. Linux will eventually replace Windows on the PC market and Mint will be there among the main actors in this new market.