You see evil villain lairs look like this (from the first Bond movie Dr. No):
It looks great in a movie but there are several problems here. First, all those people. Do you see all those people? Those are people who have to eat, sleep, go home to visit their families occasionally, go to a bar and drink (let's face it, if you work in an evil lair you aren't going to be Mormon), or do any number of other things that normal people do. I guarantee it that all those people don't live, and don't want to live, in an evil lair. Some of them may even play football (both types) or at least have a fantasy league. In addition to that they have to eat, so that place must have a cafeteria, which means it has a loading dock where all the food comes in.
So the question is, with all these people coming in and out of that evil lair, going home, or on vacation (hey evil minions have to get vacation days too), bringing in food and other supplies, not to mention fuel for their power plant (nuclear power you say? OK where did they get the nuclear fuel? It's not like you can buy that stuff online! Wait, hold on a second...I was wrong, you can. I think I am going to be on some sort of government watch list after my little Googleing session just now. Maybe I shouldn't Google "Where to buy nuclear fuel".) At any rate if you have an evil lair like that then you will have people going in and out of that place. So it is pretty hard to keep it secret.
About a week ago Randall Munroe in his What If blog where he answers random questions was discussing data centers used by Google and others. As part of the discussion he addressed the question of how to find these top secret data centers that Google has where all the Google magic happens. As it turns out that all you have to do is ask taxi drivers and pizza delivery men where they are and they can tell you (because the people that work there tend to order out for pizza alot). So how does this relate to secret lairs? Well in the movies they always portray it as this massive secret lair that nobody on the outside knows about, and the heroes have to go to great lengths to find and then enter the secret lair. I guess Mr. Bond could have just saved himself some trouble and asked the local pizza joint where the secret lair is, and then dressed up as a pizza delivery boy to get in (if Daniel Craig, or whoever is the next Bond, uses this gag in his next Bond film I claim origin and inspiration and will settle for a modest 0.25% of the profits).
The next thing about all those secret lairs is all the stuff they have in them. Do you see all those desks, electrical panels, fancy displays, and stuff? You have to buy all that stuff from somewhere, or at least build it yourself. The thing is you have to buy every nut, bolt, switch, light and relay. So where would you get all those things? Home Depot won't have them all. That's where you go to some company like McMaster-Carr. They have a catalog with all the things you could possibly need for you secret lair. It looks like this:
|That's 7 lbs 10.5 oz.|
So to make a secret lair you would need the resources of a very large company or an entire nation to build and maintain it, and even then you really can't keep it secret. But they will never put all that in a movie or TV show.