Could studying really be the key ?
Pretty much, but the kind of study needed to get to GM level is beyond most of our means. You can get to 2000+ level and still have some semblance of a life, if you're talented enough, but getting to GM level means abandoning the kids, divorcing the wife, quitting the job, turning your back on all your friends and basically becoming a full-time chess student.
Most of us, regardless of potential, simply won't be able to do that.
imagine that. maybe if you studied you'd be GM.