Lando and Charles are good, but lack the killer instinct and ruthlessness that Max has, or Michael had. Also make mistakes at inopportune times.
Until they prove otherwise, their best hope for a WDC is to have a superior car that can build them a lead, and hope that no one else catches up. Jenson also says hi.
And if Oscar continues to develop, and Lewis still has anything left in the tank, their own teammates will not make things any easier for them.