Real reason for remakes
Reason 01: Making a remake is the easiest way to make money. No need to rack your brain, no need for creativity, no need for actually bringing something new into existence, and most importantly, NO RISK involved. People will always go see a remake or a 'famous' title (like Star Trek vs. Gloober Mutants from Epsilon), it's the power of nostalgy with the lust for novelty combined. A perfect, riskless moneymaker.
Reason 02: Hollywood is a PC-agenda pumping propaganda machine. It doesn't care about telling a good story, all it cares about (after money) is keeping people believing lies (about what Law is, what government is, what social behaviour is acceptable, what 'minorities' should be encouraged and how to hate men even more, what institutions to praise, what industries to support, what attitudes to have (about food additives, for example), and so on and so forth) and dogma.
If they can hammer false values and agenda into people's skulls from when they are just small kids until they are old geezers, that's more valuable to the 'establishment' than even the money. If they can't find or figure out new ideas, new plots, new stories to use for these propaganda pumping purposes, they will simply rehash what's already been done, and just up the propaganda and it'll serve them well. If you believe you need a license for everything,
(no one can grant you a license for anything lawful, because lawful activities are not unlawful, they are already within your rights to do. And if you get license for unlawful activity, you are dealing with a criminal, and your license is not valid)
if you believe you need to register ANYTHING, if you believe you have to do this or that, or that you can't do this or that (although there is no victim), you have indeed become a good slave, easy to control, and forgotten what Law actually is. Law exists to protect humans, legal system exists to enslave them - and Hollywood wants you to think legal system IS law, but nothing could be further from the truth. Movies, however, always lie to you about this, and try to convince you that everyone has to obey the legal system, and omits the fact that there are such things as 'freemen', who do not have to obey anything, except the Law.
Reason 03: It pisses people off and makes the future seem hopeless. Depressed people are easier to control. And it leads to a chain reaction of creativitylessness (I know it's not a word, but bear with me). If you see so much lack of creativity, you start believing that creativity no longer exists, and become unable to use yours. Movies also convince you to NOT use your creativity, but instead conform to the norm and watch other people for example on how to live, breathe, dance and do pretty much anything. Originality and individuality are talked about, but never encouraged in reality. Look at all the 'embarrassing situations' in movies. Who cares if you end up in an embarrassing situation? As long as you are your own self, creating whatever you want to (not what you have been brainwashed to want), what difference is it going to make? I'll be glad to go through a little bit of embarrassment to get to a treasure chest of my own creativity! Small price to pay.
Reason 04: Changing the 'mood'. The 80's was a delightful era, full of bright, sparkling energy, that's hard to describe (especially to the ones that have forgotten, can't feel such things, or never experienced it), a certain 'atmosphere' or 'mood'. The movies made during that era not only reflect this, they shine like beacons in the mass of depravity, gloomy darkness, depressing horror crap and blackness (of clothes, for example). When a remake is made, you can bet it will not have that same, sensitive, delightful, bright, soul-caressing "aura" of the 80's, but even if it uses some of the 80's songs, it will have a soul-tearing, depressing, grey, black, gloomy or boring vibe that will pretty much suck the energy of the viewer, instead of giving energy to him. This is the hardest point to explain, but once they have 'remade' all the most important movies, and especially after the generation who remembers what 80s was like is gone, people are not going to remember the originals, nor care about them. The movies will have been "fixed" to bring the 'designated vibe' instead of giving the original, uplifting vibe of the 80's and the more free vision of the moviemakers back then.
This reason is basically like the offices in the book (ironically) named "Nineteen Eighty-Four" are doing, when they "fix" the books, the history, etc. to 'match' the current era. Movies are not documentaries, but they need to give the "proper mood" so that the viewer is kept depressed and feeling awful instead of being uplifted and having cheerful energy in him. Remakes are the logical thing to do, because that way, you can rip people away from the original movies (even if it's just by the force of curiosity) and put them to watch something similar, but "proper" instead. With luck, the viewer will then always at least remember that "proper vibe" when watching the original, and with more luck, the viewer will keep watching the "fixed" ones instead of the originals.
I would think these are the main reasons. Hollywood can't just STOP making movies, even IF it was capable of telling all possible stories during a certain time period, in the optimal possible way. So it will use any means possible to KEEP MAKING MOVIES (that do not need to be made), so that people can be kept a little poorer, so that people can be kept brainwashed with wrong values, lies, propaganda, false dogma and 'political correctness', and so that popular movies can be "fixed" and people can be kept hopeless and in despair, and in a non-creative mode.
There might be more reasons, so feel free to add them as you think them up (use your creativity..)
But this is why I think they are making the remakes.