You're posing two questions here. The first, regarding the relative tightness/looseness of the machines in today's economy, is a big (BIG) question that's kept our own Anthony Curtis busy, addressing the subject in interviews with a long list of media over the past several weeks. It's a question for another day (though, the quick answer is yes, the casinos are tightening), but there's an interesting point to make about the second part of your question that concerns the integrity of video poker machines, specifically.
The great thing about video poker is that you can tell exactly how "loose" (full pay) or "tight" (less than full pay) every VP machine is simply by reading and analyzing the pay schedule. There are hundreds of variations of video poker machines, but for each and every one, the return percentage can be quantified -- as long as the machine is fair and legal. And this is the crux of the answer to this question.
In most gambling jurisdictions, video poker machines must deal hands randomly from a full deck of cards. If the machine is programmed to abide by gaming regulations, the only way it can be "tightened" is by changing the pay schedule, which also means posting the lesser payouts for all to see and analyze (unlike slots).
Of course, a video poker machine is just that -- a machine -- meaning it can be gaffed (rigged) so that it doesn't deal from a full deck or in random fashion. But if a casino were to do that it would be cheating. And if it got caught, it would probably drown in the all the hot water it found itself in. This means that if you know enough about video poker to understand what constitutes a good schedule, and you find one in Las Vegas, you can breath easily that what you see is what you get.
It sounds like you're experiencing, in layman's terms, a streak of bad luck: "... winning hands occur less often than in the past." It's interesting (and human nature) that it's easier to accept "good luck" when winning hands are occurring more often than in the past, but when they occur less often, we start to suspect there might be something else going on.
