To answer your original question, it's hard to brand and market, look at his products they quite varied and have obvious sounding names. Regarding legal he's a solopreneur, they likely operate from the same legal entity behind the scenes
How does that work practically? If I found a startup with 5 product experiments, can I honestly say I have experience creating 5 different startups? Does every pivot count as if you made a new startup, and it’s not the original startup anymore? I’d always thought a startup was a company, but it seems it means something more like a landing page? Genuinely curious.