Valtteri Bottas wants to stay at Mercedes in 2019, as any driver in that situation would, but he's also a pragmatist. That's why he's admitted to considering a 'Plan B' just in case he is dropped in favour of Esteban Ocon, which remains a possibility given team boss Toto Wolff admitted before the start of the August break that this was the choice with which he is currently grappling.
Being cast aside by the best team in grand prix racing seems like the death sentence for a career, and it would be a body blow for Bottas. But it would be far from fatal, because once spat out from Mercedes he should be able to choose between a Plan B, C and D - and perhaps go even deeper into the alphabet given the experience and qualities he could take to a rival grand prix team. If the worst happens, most of the other teams on the grid should seriously consider signing him up for 2020.
That might seem like picking up a washed-up has-been - a failure who, axiomatically, would have been conclusively proved to be of no value because he's been discarded. But that's a fundamental misunderstanding of the challenge he faced at Mercedes and the reasons he might be dropped from the line-up. He has a huge amount to offer.