Former executives at Tesla, who have seen the early-day struggles of the world’s most famous EV brand, have raised more than $26 billion after leaving Tesla to develop their own green energy startups. More than 30 startups have been either launched or led by ex-Tesla managers, and those firms have raised billions from investors in the past decade, according to an analysis of The Wall Street Journal based on data from PitchBook. Executives who have co-founded Tesla, worked on its first-ever vehicle, Roadster, or presided over…