I would say yes that applied until a year or two ago however that advice was usually directed towards regional pilots with several thousand hours of 121 time when getting a “bite” from a legacy was few and far between. Like you said regional FOs are getting picked up directly by the legacies, the game has changed dramatically in the last 12 months….. from your level of questions honestly it would do you well to get to know urself around the 121 world a bit more (I’m talking months not yrs), before you jump to a “major” just as a means to an end to jump to a legacy…. You’ll probably end up at a legacy in the same amount of time as if you went there directly but be a far less seasoned pilot once you get there since half your career will be spent awaiting IOE or in the schoolhouse. Best of luck regardless. Apply to where you could feel comfortable staying for the rest of your career, if that’s JB by all means go for it (with the eye of possibly moving on in due course), if not do yourself a favor and don’t bother, cause as you said once the music stops…. It stops.