Reach is how many people see you. Trust is how many would back you. They feel related, but they aren't, and when you need something real, trust is what counts.
The clearest argument for this is an essay Kevin Kelly published in 2008 called 1,000 True Fans. Kelly defined a true fan as "someone who will purchase anything and everything you produce." Then he did the arithmetic. If each true fan spends $100 a year on your work, 1,000 of them add up to $100,000 a year, which, minus some modest expenses, "is a living for most folks." He admitted the formula might be off by an order of magnitude, but even then, he said, the number you need is far less than a million.
Notice what that number isn't. It isn't a follower count. A thousand people is a small room. But if they would buy anything you make, that room pays your rent, and a million people who scroll past don't.
Paul Graham makes the same point to founders. Crediting Paul Buchheit, he wrote in 2009 that "it's better, initially, to make a small number of users really love you than a large number kind of like you." He said he mentions it to every startup Y Combinator funds, and that if he could tell startups only ten sentences, this would be one of them.
Why does a small room beat a big crowd? Because people who trust you do things strangers won't. They come back. They bring their friends. They give you the benefit of the doubt when you get something wrong, and they buy before you've proved everything. A crowd that merely likes you does none of that. It keeps scrolling.