If the business and team were phenomenal, the attire wouldn’t have mattered.
However, dressing appropriately for a meeting is an easy way to demonstrate that the person is taking the situation seriously and being respectful of the other parties. If someone can’t make the effort to dress appropriately for pivotal VC meetings that decide the future of their company, it’s likely they won’t bother taking other meetings seriously either: Meetings with customers, partners, recruits, and so on.
As a VC, you don’t want to fund someone who will go around being disrespectful, intentionally or otherwise, thought your network. We like to glorify the exceptions like Steve Jobs, but the reality is that dressing appropriately to show respect for your business partners is a fact of life.
In 2021, it’s cheap to dress in a presentable manner. You don’t need a suit and tie (west coast, anyway) but you do need to make a basic effort.