It would seem a very rational thing to do. You pick the game of your choice, learn the fundamentals and mechanics of solid play and then slowly become a winner in that game. Though you don't quite know fully what you are doing yet, you try some creative plays and some of them turn out to be brilliant. Perhaps you got a little lucky here and there with these plays, but mostly they were fundamentally sound and based on good observation of your opponents and the flow of the game. You congratulate yourself and vow that you will do these good deeds again. Well done!
On the other hand, during your experimental phase you also make some plays that don't turn out quite so well. Actually, that is an understatement- they are monumental fucking failures. In fact, had you eliminated two of the plays from your session, you would have actually come out a small winner for the day. You take these harsh lessons to bed with you, only this time you vow to never make these plays again.
Now that you are bumping around less frequently in the dark and have pruned all of the major atrocities from your game, you start winning fast now...and BIG. You could keep on trying new things, but you are a professional and you have bills to pay, so better to just stick with the formula- at least for now.
Right now I play x tables with y win rate for z hours per week. If I play x + 3 tables for z + 15 hours a week, even if I can maintain a win rate of just y - b, I can pay off my car and my credit cards in 5 1/2 months!! ...And all I have to do is keep doing what I've been doing!
Except for one tiny little problem...it just doesn't work anymore. Is it the variance? The bad beats? The fact that your opponents are catching on to you? Perhaps a combination of all these things, but they are merely symptoms of the real problem. The real problem is that by failing to react appropriately to the situation at hand yet still playing fundamentally decent in a formulaic fashion, you moved from an exploitative/optimal strategy to one that is only approaching optimal, at best. This what occurs when you begin applying your commonly most effective lines to every single hand.
Once this finally dawns on you, it truly becomes easy to understand. Your best lines were developed in response to game flow that existed THEN but is not likely to be present NOW. In the past, you were to trying to play GREAT, not just ADEQUATE. However, in all likelihood, the lines that you are using formulaicly at this point are probably rarely awful, but they also going to rarely be great as well. And great play is what creates good win rates and solid monthly incomes. Making the occasional horrific play that you would not normally make is not necessarily something to be avoided at all costs, but rather shows that you still have blood pumping through your veins. The only types of plays that should be cut completely from your game are those odds defying blundering all-in calls on the turn.
By emulating your past success, you are settling for mediocrity and being just plain lazy. The bottom line is very simple- you must strive to get a little bit better every day. That is how you got to where you are right now. This is the very minimal requirement, even if you plan on only keeping your current win rate. As they say "if you aren't slowly getting better, you are slowly getting worse."