I liken it to the desire that many average Christians have to win the lotto or suddenly come into wealth. "Lord, I'd tithe - I'd give above and beyond! If you blessed me with riches, I'd be SO GOOD with them! I'd bless the socks off my local church, and give to missions, and go on missions, and travel the world spreading the gospel, and... and.... and..." The truth is God entrusts us with plenty, and we need to be good stewards of that which He has entrusted us.
The truth is if we were given more, we would follow similar patterns to how we currently live. We would be more extravagant in how we currently operate. For those who are already spreading the gospel, then yes! It's reasonable to think that we'd respond to added resources with added enthusiasm and be even more extravagant in our evangelistic efforts! For those who don't make any time to evangelize, it's unreasonable to think they'd suddenly make the time to do so. For those who pour into others with what little they have already, it's reasonable to think that they'd respond to being given more by giving more. For those who are miserly with their time and resources, it's unreasonable to think that being given more would result in a sudden change of heart or lifestyle.
It's no different for a worship leader.
God can raise the most lowly shepherd to be the king of a nation; He will raise us as high as He wants us as fast as He wants, but we need to be good and careful stewards of what He's already given us before He'll entrust us with more.
I know my calling is as a shepherd, to care for a particular kind of sheep, to train & equip others to do the work of ministry they've been called to, and that involves sending many musicians out into the world - to other churches, to missions, to bands, to be itinerant worship leaders. I'm extremely satisfied in where God has me, and I'm continually humbled that He has allowed me to be part of shaping and assisting others to grow in their gifts and talents. There's a small part of me, my artist's heart, that does wish God would use one of my songs to bless the many, but the most important thing is that I am useful to lead my local church into His presence and to pour into others what has been poured into me, for God's glory and not my own - and that is more than enough :)