I disagree partially on the quality issue; while it's true that you can't turn a crappy piece of meat into a delicious entree, most of the steaks you're ordering in restaurants are the same grade available in stores. Prime is a rare find in US supermarkets and butcher shops alike, as was mentioned, most of the prime meat goes to the best steakhouses. However, just as prime meat makes up a very tiny portion of the beef market, the steakhouses that sell prime make up a very tiny portion of all steakhouses. The fact is, if you're eating prime beef, you'll definitely know it by the emptiness of your wallet.
Most steakhouses serve choice beef, and in most supermarkets you will find both choice and select beef. While in theory it's true that choice will always be better than select, and prime will always be better than choice, I think it's much too easy to sit back and say that the beef is doing all the work. The very BEST steak I have ever had, is from a local steakhouse, well-known in our area, but certainly not a fine-dining type of place, serves choice beef. My father, who has been eating there for much longer than I, has made it a personal mission to try to find a better place than the one near our home. About a month ago he went to a famous Chicago steak house, and paid somewhere in the neighborhood of $70 for his steak, and while he admitted that it was more tender than the local joint, he said there was no contest in flavor.
I think what may happen at some high-end places, is that the owners don't truly know how to handle their wonderful product. They think because it is prime, the ingredient will do all the work for them. Thus, things like proper seasoning, proper garnish, proper heat, and proper service fall out of the scope in favor of simply procuring the best beef possible.
I've been to a few different places where I was appalled to find my steak served to me already sliced! God knows that the busy line cooks didn't let that steak rest before they sliced it and threw it into the window so they could work on the next order. And all of the juice was just streaming right out of my poor steak.
If you want to make great steak at home, you need to handle the ingredient properly. Season it well- SO many people underseason their food in general, and their beef in particular. If you're grilling, make sure you get your grill the very hottest it can possibly handle before you put the meat on. If you're pan-searing your steak, you want your pan smoking hot, literally, and if the fire alarms don't go off a few minutes after you drop your meat into the pan, you're not getting your pan hot enough. Don't overcook it! Even a well-done steak, done properly, should not be dry. Remember to compensate for the carry-over cooking. You should let your steak rest at least 5 minutes before serving it, and this time will also continue to cook the meat. If you want to garnish your steak, which is certainly not necessary, keep away from bottled sauces, and go with garlic/herb butter, or pancetta butter, or just plain butter. Save the worcestershire for Ceasar salad.
If you think you're doing everything right and still aren't getting the results you want, there is 1 marinade I will recommend, and it is the ONLY marinade I will recommend: Marinate your steaks in the fridge for 2 - 3 days in olive oil (VO if you can afford it, though EVOO is probably unnecessary) crushed fresh garlic, and crushed peppercorns. This is the only marinade I have found that will compliment the flavor of the beef. Wipe the excess oil from your steak before cooking, and remember to season it, cook it at high heat, cook it to the proper temp (get a thermometer!), and let it rest.