In some cases, those with less experience are threatened by people who have more, and if a company has a low median age experience might be an issue to the interviewers. The problem is exacerbated when the interviewee is not impressed when the latest, bleeding edge tech is in use at the target company, and has seen similar projects completed with stable and boring tech.
In others, especially those with the high-strung startup mentality you mention, they are looking for people to work more hours for less pay and promises. Younger people are more able / willing to take risks. Experienced workers are not as interested in promises, but prefer defined returns on their individual investments.
In others, especially those with the high-strung startup mentality you mention, they are looking for people to work more hours for less pay and promises. Younger people are more able / willing to take risks. Experienced workers are not as interested in promises, but prefer defined returns on their individual investments.