Why can I not score well anymore?

The reason you're not scoring in the 70s now is because you're writing down numbers that add up to over 80.     Sorry, but such an incredibly vague question gets an equally useless answer.    

 

Seriously, if you were shooting in the 70s you must have some notion of what's going on - you can't be that unknowledgeable.   Perhaps if you shared details you'd find some helpful advice.  

Take a step back.  Check and doublecheck all the "little" things.  Is your grip a little different than before?  Have you unknowingly allowed the ball position in your stance to move a little bit? Have you checked your alignment and setup? Sometimes it's nothing more than some little thing that has changed.  Especially for accomplished golfers.

Still not enough detail. Is the trouble all through the course or is it a certain type of shot(s)?

 

Since you mentioned comfortability and confidence, I will just say I have noticed over many years in myself and others that when those are not present, tempo is the first thing to go out the window. For some reason, when you are unsure of yourself, your brain thinks that hitting the ball quicker and harder is the way to deal with it. I just had a re-adjustment a few weeks ago where I returned to solid ball striking by slowing it down a bit (esp the transition).

What are you having trouble with? Long game? short game? Where are your misses goin?

I am sorry J, but I think your mysterious problem of no longer playing well may be just an unfunny attempt to elict responses from serious golfers.  Someone with a 4.6 index isn't going to turn into a hack over night.  You would have seen a professional or gone through a series of changes in an attempt to fix the problem.  But no, you just suddenly appear asking for assistance to a very vague malady.  Prove me wrong.

he has charles barkley disease lol

Which only goes to show, we must suppose, that even low 'cappers can start making basic errors again and have difficulty self-diagnosing them. That is something I can believe. At a higher level this game is so much about confidence, which comes from a presumption of subconscious skill. When that goes south you need to buy a video camera or take a lesson. Trying to just play through it or bashing away on the range may not do the trick.