This article and the study referred to, seems to confuse shyness with introversion.

For clarity, "introverts are drained by social encounters and energized by solitary, often creative pursuits" (Psychology Today).

Of course, if you are shy / socially awkward / anxious you can (and should) take steps to overcome that. It's a no-brainer, that you will feel more comfortable and social interaction would be less taxing. However, if you are an introvert, even if you are comfortable and having a good time, you won't be able to keep up with the extroverts. They will be energized by social interaction and you will be depleted by it, no matter how pleasurable the experience. You are simply wired to process stimuli differently.

That is a fundamental difference, the reason why we even have these terms (intro/extravert) in the first place.