Then you are doing them wrong or have the wrong attitude while doing them. Stretching is about teaching your body to relax at greater and greater ranges of motion. You can use "enhancement techniques" like reciprocal inhibition, PNF, or myofascial release to speed up the process, but ultimately that's what it's about. You also seem to be someone who is bordering on learned helplessness (you seem to believe that you are doomed to never succeed) and you seem to suffer from paralysis by analysis.
For the next week I want you to stretch with the idea in mind that:
"Static stretching is effective"
"You are flexible and your muscles can elongate naturally"
"The initial tightness you feel when you perform a stretch is not your actual range of motion, but only how far you have become accustomed to moving that joint/muscle"
"When you feel tightness in a muscle during a stretch you job is to relax that muscle and then move into a deeper stretch"
"Approach stretching like you would have when you were young and supple and didn't fear hurting yourself or need to guard against your muscles stretching"
Obviously there will be an actual limit to how far you are going to be able to do this on any given day, but if you do this every day you should see improvement after a week of this. No, you probably won't be dropping down into the splits or standing back bends, but you should see improvement nonetheless.