The situation is what it is Dave. There is probably a series of events that prevented contract talks happening early. The ownership change, Martinez and his poor management contributing to RB's dip in form, Martinez getting the sack, RB going away to a European final (to not play) and then Koeman coming in and taking time to assess his new squad. From the looks of it contract talks started Christmas so 5 months into Koemans reign. It should never have gotten to that poiint but we are where we are and that's RB has turned down an incredibly generous offer, especially when you consider how poor he was during Roberto's last two seasons.
The club will sell him and i imagine his agent has already agreed terms with someone because otherwise what would be the point in turning down a contract and risk being sold to some mid-table side. I expect he'll be at Spurs or maybe City because he helps their homegrown quota. Maybe the change with finally make him the player he has the potential to be, maybe it won't and he'll be sold to Watford or somebody - who knows.