Putting conspiracy theories to one side....
What we see with Merc is a team going through growing pains. Their weakness in recent years has been in the design of the car, so they have worked on fixing that. So now their weakest spot lies in the strategy calls. They'll fix that and then we'll see the next weakness, and so on.
Each iteration will build their resilience, you have to go through these bad times to develop maturity and strength. That's why Ferrari and McLaren always seem to come out on top even when they do really stupid things, it's down to depth of experience, someone in the team has been through it before.
Merc just need to go through the the learning curve, there'll be more weak links to be resolved before they become a reliable WCC team