They "underpay" compared to Google, etc and compared to the Bay. But Shopify is a Canadian company first (I'm in the US) and they pay me a salary well over the average for my area (double), not much less than what I was offered by other remote companies (within ~$10k) but pushed north of $200k/yr by adding stock.
We also recently received info on a new pay structure that basically lets us choose how much of our TC is $$$ and how much is stock. We're excited and people will be given raises. There are news articles you can read online.
Shopify also aims to be a "100 year" company. It means not paying in the top 10, but also not overworking employees or firing the bottom 10% every year.
As someone who isn't in the Bay... they pay just fine for new hires and for tenured employees once they finish raises.