me playing guitar (don't act like you're not impressed)

have you ever tried playing a musical instrument before?
It's not like riding a bicycle; if you don't practice every day (or at least once a week) you actually lose skill.
Most people don't have the time to throw away learning to play an instrument, and getting really good with that instrument. However, if you have a record deal, then you are getting paid to throw time away learning the instrument to mastership -- therefore, mainstream rock bands tend to be better than underground (the exception of course is the majority of rock bands for the past 10 years)

look at this guy thinking that popular music is the most talented