I assume you are referring to GitLab, so yes. GitLab and Bitbucket are both actively releasing new features and have sizable paid user bases. GitHub is the market leader, no question, but it not nearly a monopoly.
"Can a company that's not even close to profitable be considered a "market leader"?"
Sure it can. Uber and Twilio are generally considered, far and away, as market leaders in their respective spaces; Uber is massively unprofitable and Twilio was operating at a loss at the time of its IPO.
Market leadership is a function of production and capacity, not profitability.