Every other electric car has to rely on a broken, sparse, expensive charger network. Blink chargers and some ChargePoint chargers are expensive in many places ($2 an hour!), and Blink is notorious for having broken charging stations. There's 4 ChargePoint stations in a garage near me that have been broken and unmaintained for years, and they're out of warranty and the mall doesn't have a financial incentive to fix them.
And then there's the DC fast chargers. I'm not aware of a single BEV (Volts or other PHEVs are excluded here) that can travel across the US with a reasonable route without worrying about finding chargers along the way. In fact, last time I looked, there was no physical way I could do a road trip I've been meaning to do through the western US in my i3 (my car, of course, has half the battery range of a Bolt) because of a lack of chargers.
Tesla's Supercharger build out is extremely important to their future. Until other companies step up and install DCFC stations everywhere (and figure out the CCS vs CHAdeMO format war), Tesla is going to have a massive advantage. Sure, not everyone is going to want to do a multi-thousand mile road trip, but driving one of Tesla's cars might make them.