The gross margins on EV chargers are likely pretty good as you say. But is there any evidence that these networks actually turn a net profit? These charging stations are very expensive to install and require ongoing maintenance/repairs.

The only charging network I know that is publicly traded is Chargepoint, and they have never turned a profit. In fact, their losses have increased as revenue has gone up. But, they are not a perfect example since their chargers are independently operated with prices set by the operator (with prices anywhere from free to significantly in excess of retail electricity prices).