In my experience, at three years cellphone batteries are somewhere between 30 and 50% of their original capacity, and that is with charging every three or four days.
If EV batteries follow the same trajectory they would be borderline unusable in three years given that you are not supposed to use more than 60% of their capacity in the first place.
I was worried about the same thing until I realized that phones are charged at a much higher speed relative to battery size than EV's are.
Charging time for my phone from 0% to 100% with my stock 5W charger: 190 minutes (3.2 hours). Charging time for my EV charging at my usual lowest Level 2 charging speed (5.6kW) from 0% to 100%: 13.8 hours.
I charge the EV slowly both to extend battery life and to minimize how often the total load of my electrical panels exceeds my solar inverter capacity so that I minimize how often I pull from the grid.
I usually charge it from 40% to 80%, not 0% to 100% (going to 100% once per month to reset the battery cells, or if I'm about to head out on a long trip). I don't even charge it to 80% every day (if the EV range is more than what we need for the next day's driving we'll charge it further to 80% only if it's a good solar day with free power). And so far I haven't seen a reduction in range in the 17 months and 40K miles we've driven it.
At least that's my use and experience. I don't know about with others.