Investors have a lot of faith in Elan because of his track record of achieving very unlikely challenges (design and mass produce electric cars, design and launch rockets, ...).

The problem is that a lot of its supporters and investors cannot distinguish between solving complicated problems (the ones Elon Musk excels at) and complex problems (the ones Elon Musk is trying solve now: FSD, robotics, etc...).

For reference, a complicated problem is one that you can break down into pieces and solve each individual piece within some tolerance and as a result solve the whole problem. For example, how do I build a rocket that can get X kg of load at a given orbit or how do I design an electric car to transport 4 people 200 miles.

Complex problems are problems you cannot break into pieces and plan for before hand, usually because you have unknown unknows and you have a lot of feedback loops (when you change something it changes something else you though you had already solved). This are the types of challenges Elon is taking on now: FSD, robotics, etc...