1. It's a 30 person shop
2. Author makes 3x the juniors
3. The juniors don't think author is worth 3x them
4. the HR person was a bad hire
Dollars to donuts this is a very poorly run company (each of 2-4 essentially prove so alone, so they definitely point that way in combination).
Let's assume developers (cause I'm not qualified to talk anything else). Let's assume the 50/150 since 150 I'd estimate is about market for a senior dev at least in CA at that size shop. Juniors are more like 70k (or more? I may be a bit out of touch), so 50k is 40% short.
The chances that the junior folks are paid well short of market with great equity and the senior hire is market with little equity? Yeaaaah.
Honestly in my experience it's more likely that everyone at this company is fucked for equity, and everyone that didn't know better was fucked for salary also.