We are men, well, human beings living in temporal reality-in time. Time is a measure of change, and thus tomorrow never comes refers to the fact that the only TIME we can actually live in is NOW.
Tomorrow refers to time which will be our now when we get there, but as soon as we get there it becomes NOW, not tomorrow.
TODAY is the First Day of the rest of your life – which we are guaranteed NONE.
Thus the NOW we are living in is the first day of the remaining days we have left on this earth, which has no direct relationship to the fact that we are living in an eternal NOW.
Your knowledge is shadowed in infinity, so where you place your observation is technically a first day. In that, tomorrow would never come because where you are is the only part of your existence where the you maintains focus in this dimension. Your essence flavors and shares a truth in creation of everything. Everything came from nothing, so as eternity unfurls in the finite we begin again and again to fulfill who we are from what we are not? Do you see before you open your eyes? The purpose in who you are is in being aware that where you are is the tomorrow today of yesterday. No tomorrow for today is the only moment that is you.