Most people in the industry will concede that Tesla forced everyone else to up their game. Tesla were unreasonably ambitious, but that ambition lit a fire under the established players.
Between 2010 and 2015, the Leaf had a 24kWh battery. They added a 30kWh option in 2016, then launched an all-new model in 2017 with a 40kWh battery. At this year's CES, Nissan announced a 64kWh model. There's a clear inflection point that coincides with the announcement of the Model 3, which is matched by several other manufacturers. The huge amount of media attention and customer interest convinced the motor industry that there is a substantial latent demand for affordable EVs with >200mi range.
It's perfectly reasonable to argue that established manufacturers are making better EVs because the technology improved, but Tesla drove a lot of that improvement. They were the first manufacturer to grasp the significance of battery thermal management, something that Nissan is still struggling with. They were the first to demonstrate the improvements in interior capacity and comfort that come from a purpose-built EV platform rather than retrofitting electric propulsion to an ICE platform. The threat posed by the Gigafactory persuaded/forced LG, Samsung and Panasonic to seriously ramp up production of 21700 cells.
Tesla aren't a great car company in my opinion, I think they're hugely over-valued, I think there's a real chance that they'll be bankrupt within the next five years, but they did something very important by taking a moonshot on a truly modern EV.