I don't think there's a threshold for at what income level you can start shopping a Hermes. It's all a matter of your financial comfort and priorities! Like someone with household income of $300k might not feel comfortable with buying even 1 Birkin, while someone with household income of $100k is comfortable with buying a couple Birkins. Some people have the disposable cash savings to just pay upfront, others have to save up and cut spending elsewhere. Regardless of the financial background, those who do end up with Hermes items, do love what they bought!
So I agree with everyone who says don't feel pressured to spend a lot of $$ there, go for what you happen to love. It seems like these days, half of the people who get their first Birkin or Kelly happened to get lucky, without having to build a profile of many items with the same SA. I'm also just beginning to explore Hermes because I always thought it was for the uber wealthy too (which I am not). I mean, $10k+ on a bag?? Maybe the uber wealthy can have hundreds of thousands of dollars worth of Birkins, but it doesn't sound crazy to me anymore to own 1 (or 2, or 3...haha). And my husband actually agreed that I shouldn't wait until I'm "too old" to enjoy a Birkin.