People are just diving a lot and there is still far more ICE vehicles both on the road and being purchased than electric vehicles. Since cars last an average of about 12 years these days EVs have a lot of catching up to do. Tesla is building chargers as fast as they can go though. Several have opened near me in the past year. The rate is expected to pick up rapidly as Tesla now qualifies for government financial assistance and virtually every EV made will be built to accept Tesla chargers by the end of the year. Competitive charging stations are picking up the pace as well.
Tesla charge stations don't put up big signs to attract your attention. That is not needed as the cars already know where the chargers are. Since charging still takes longer than fueling Tesla places most of their chargers in parking lots where food and activities are available to help pass the time while holding down Tesla's building costs. If you are not looking for a row of chargers in parking lots you may never see them. Also, the vast majority of charging for most EV owners is done at home. I have about 30,000 miles on my Tesla and it has been to public charge stations less than 20 times. Most of the time it just charges while I am sleeping. No lost time or mileage getting to gas stations.
Tesla North American charging stations
The red dots on the map are Superchargers and the grey dots are destination chargers. The charging costs at most destination chargers is paid by the destination to promote their business. They are only about 5% as fast as a Supercharger but have no trouble getting the job done over night.
You can manipulate the map to zoom in to any area you are interested in.