Of course they have more tech than they tell us. They shouldn't tell us everything.
Assuming it's the US government that you're talking about (although something similar can be said for all nations), one of the elements of keeping your country as safe from threats as possible is to never consider your position safe. Okay, the Soviet Union collapsed. Yippee! No more enemies, right? We can all throw away our guns and go play in the wildflowers, right?
Wrong.
The first threat to the free world is terrorism. Terrorists are not just a bunch of screaming fanatics. They must be regarded as an organized army. Underestimation of a lunatic is a fatal mistake.
The second threat to the free world takes the form of hard-liners of the old ways, people who do not agree with the current turn of events, and these were people with connections. Right now, we (the US) are the biggest, baddest dog on the block. We intend to keep it that way.
Regardless of what we may look like on the inside, compare us to the rest of the world and we have the most stable system around, such as it is. As reliant as we are on Asian markets, the Asian Pacific Crash barely caused a ripple in our infrastructure while it devastated most of the others dependent on that market.
The reason our government doesn't share all of its secrets, even with it's own people, is because we want to keep what we've got. The best way to defend what we've got is not to make our defenses and offensive capabilities known. The other guy is a lot less likely to pull his knife if he thinks you've got a gun. It's a game of international poker. "We can nuke the world and come out smelling like a rose." Are we bluffing or not? Who wants to be the first to find out?
There's a lot more to this, but I have to get to work. If you live in the US, rest assured that even though the fatcats in DC don't seem to give a damn what happens to the rest of us, they haven't pushed the button yet, and I can remember a time when they almost did. It's an uneasy peace, but I sleepp well enough at night.