I do not think this is true of all dyslexic learners. A friend of mine has a nephew who was identified as a dyslexic learner just before his A-levels. Her relief was massive as she had struggled for years to get him help for something no-one seemed to want to acknowledge; however the amount of support he received after acknowledgement was incredible. He received a specially modified laptop, support and extra time for handing in assignments, to mention a few. He is now enjoying university.
It is, however difficult to imagine his frustration up until this point. He may suffer with self-esteem issues throughout his life because he never felt he could keep up for so many years ..years which he was ignored and reprimanded.
For someone whose dyslexia is not identified, their coping strategies may see them through but never to their full potential. Surely their angst coping with traditional learning would have a severely detrimental effect on their self-esteem.