There are always people who say "XYZ doesn't work" and for them nothing usually does. EVERYTHING works . . . some things better than others . . . but you can make anything work.
The real issue is what you're trying to do.
If you are trying to develop a methodology that will help you understand the market and be able to make a highly accurate prediction at any point, then you're in for a lot of hard work. There's a great chance that you don't have the know-how, IQ, funding or tools to succeed. You're going to become a statistic.
If, on the other hand, you are TRYING TO MAKE MONEY . . . it doesn't take a lot to do it. Develop a simple method that will earn you $100/day. When you have your hundred bucks, quit for the day. Go do something else. Do that every day. Increase contracts slowly, say one a month over 5-6 months.
By setting yourself up with simple, low expectations, you stay away from all but the highest probability plays. (Of course, this assumes you have the patience and self-discipline to wait.)
Here's an example of a simple way to do this with linear regression:
Wait for the 9 pd ema to be above the 18 pd ema on the 15 min chart. Once it is, look for the same alignment on the 3 min chart. Wait for a pullback. Draw the LR channel. Enter on a breakout of the LR channel. (Don't like the 9-18? Use the 5-35, 5-15, 5-20, or whatever suits you.)
So, please don't say that "linear regression doesn't work" . . . that is simply a false statement.