It's probably not impossible, but we'd have to renegotiate Browns entire deal in order to do that. I'm not sure you can just click your fingers and pay people more on any given year just because you feel like it.
Regardless of how the player feels honestly, I think it's a shit idea strategically for all but yeah, perhaps the longest term contracts. Obviously you're not going to get squeezed by Brown at any point because you've already signed him for his whole career. Not against that in principle, but we'll be digging our own grave if we go nutty with it. As I said, it's a short term recruitment strategy imo, which is miles from where we are right now.
But yeah sure, front load Brown a bit. I don't think the NRL will let us pay him 3m next year though. If we're all being honest, we know this isn't really likely to be happening to any great extent anyway. We're just spending dumb money in dumb places just like we always do. The Taj Annans of the world are delighting in our stupidity.