Although you quoted somebody other than myself, as above, let me once again say that it’s daily practice which makes all the difference. For instance, there’s the flute, and then there’s the player, but flute playing simply doesn’t successfully happen until there’s an integration of both the flute and the player, that the flute becomes an extension of the player. True, a professional player generally does put in a lot more practice time than an amateur, day by day, but it’s also true that a successful amateur needs to develop that same level of integration, and, quite honestly, that can only be done with regular (read: daily) contact with their instrument.
Moreover, it’s well known that an instrumentalist, of any instrument, could have both good days and bad days. Yet, much could be lost were an instrumentalist to not practice on the bad days. So, even on the worst of days, a player does well to at least commit themselves to a daily warm-up routine, nothing strenuous but of perhaps fifteen or twenty minutes a day. On my worst of days, for instance, I’ve done just that, after which I’ve then packed-up my flute, and have then gone on to do something else, BUT, I at least have the satisfaction of knowing that I’ve completed my daily commitment. That’s crucial.
Oh, sure, it’s also possible to play for hour after hour, and to completely loose track of time. However, if a person could be really serious about developing their abilities, then that person could do well to commit themselves to at least a daily warm-up, if nothing else.
And, let me add something that James Galway once said, that if a flute player could intend to be a professional, then that player could expect to have a flute in their hands for every day of their playing career. And, that says it all.