I'm not really a good example, as I'm not really interested in any more competition than the occasional rimfire shoot, or trap round, however I'd like to point out that the last vehicle I bought was $850, and will soon be my daily driver, probably replacing my $1000 current DD which will be sold.
Point is that as with many things, cost of entry will remain a barrier to many people. This is the case with everything from ham radio to trackdays to nordic skiing, or anthing that has a decent amount of hardware investment.
I have to say I can see both sides of the "costume" debate, as for me, boots, jeans, and a button-up shirt is my definition of Sunday Best. I don't generally dress up for things, though, as I wear a uniform for work 5 days a week, and don't feel like going anywhere where I have to wear a specific thing.
I'll stick with the initial investment being a significant barrier for most people. That can be offset by loaning, however if someone isn't convinced they might like it, they probably won't show up. Your best bet would probably be to pound feet, and spread invitations word-of-mouth. Especially by talking it up with people you meet at the range.