He wasn't exactly portrayed as a symbol of trust in the media. I guess you could say, for PR purposes, his active involvement became a liability. I don't see Uber having trust issues as a result of him leaving.
I'm guessing he just wants to move on.
So if you think that the board might be held liable by shareholders for something in the future it is usually a prudent step to create as much distance between you and the board as a shareholder as you can so you don't end up on both sides of a lawsuit.
I guess the reputation cost is a good point, but Kalanick is always going to be associated with Uber, whether he's officially on the board or not.
That said, its more like a 5-10hr / wk commitment, not a full time job.
Certainly, being below a certain threshold would be one important factor.
He was a contentious figure, and Uber might want to see him off - remember that he got in a huge boardroom war with other board members - so this is likely something they want. His departure could have been part of the long term deal, or possibly in his contract somewhere.
Though there's definitely cred in having the founder around, I suggest this is not that kind of situation.
There's only so many board seats as well, there may have been angling for others to step in.
Personal choice matters a lot as well - he simply may not really want to do it for a variety of reasons.
To me it seems there are no hard rules for boards: it's not like hiring staff or even execs wherein you're generally looking for things, often, the board is just the 'gang of people with the power' duking it out for influence and control etc. so things can be very nuanced, political etc..
He exits his position in a way that can hurt the investment optics of Uber.
He didn't do that, though. He exited his position predictably and without huge newsworthy sales. As usual, Levine puts it better than I can; from https://www.bloomberg.com/opinion/articles/2019-12-17/the-se...:
> There is nothing particularly strange about this. At one point—basically before June 2017—Kalanick was the founder-CEO of Uber and owned an appropriate amount of stock for a founder-CEO, and now he is not the founder-CEO and is working his way down to an appropriate amount of stock for a non-founder-CEO.
…
> He has sold stock every day since the lockup expired. He has accounted for about 7.8% of Uber’s volume during that time
For Travis, it's his time and possibly something that prevents him from creating another company.
For shareholders, it's a cost of an advocate and vote. They want someone there who will represent them the best.
Based on this article Cloud Kitchens is competing with Uber Eats so my guess is that's why.
https://en.wikipedia.org/wiki/Travis_Kalanick#Criticism_of_K...
If it is voluntary, then they step down because they want to ( for whatever reason - pursue other opportunities, etc ).
If it is involuntary ( forced out ), then it's pressure from shareholders ( especially a major shareholder or a group of major shareholders ).
Board of directors are elected by shareholders and they serve the interests of the shareholders. Only shareholders can remove board of directors. Of course if you have more than 50% of the voting shares and are on the board of directors, then you are golden. In that case, only legal action could get you removed, but that bar is very very high.