There are so many variables, it's hard to know what the best case scenario could have been if the breaks had all gone our way. Obviously, getting time at Sony's E3 conference was HUGE. But, what would have happened if they had great test footage, focused marketing communication, no inflated Shenmue I/II cost to compare with, Sega had Shenmue HD Remaster ready to go out the door following E3, and none of the clickbait media? It's hard to say but I think $10m might have been attainable if the cards had played out the right way.
Overall, we shouldn't ever be upset by what played out. The game has $6.5m (and counting) along with other undisclosed sums from investors. None of the money will be going to publishing thanks to Sony and we're getting the game we've dreamed about for so long.