They always keep some.
They still have their last monument winner on the team. And their last GT podium finisher too. They both signed new contracts this year and will stay with the team until 2023. If they contracts aren't sold to another team before they run out, like the one of Martinez, that is.
But yeah, they'll always keep losing biggish names faster than acquiring them if they continue having one of the lowest budgets in WT. Even more so if the situation keeps getting unstable like in 2017 or 2020. I wonder what are the reasons for Vaughters being unable to secure higher sponsorship deals for so many years, a lot of the time in the past his team offered a very good return for money.