If (a) most sustained changes require a change in circumstances (not willpower) & (b) exceptional performers across activities do things qualitatively differently from typical performers, perhaps we should expect "I'll push myself to do more x for better outcomes" to usually fail
Obviously it's possible to modify circumstances by use of willpower, and this is indeed a very sensible thing to do if (as I believe) it's unreasonable to expect that you'll be able to sustain a constant willpower drain to alter behavior in the long run.