Modularity. Nobody wants to spend $3,000+ to replace a battery. Until it's possible for the average consumer to replace a battery module nobody is going to trust electric vehicles.
It's probably accurate that given the choice not spending $3000 to replace a battery and... spending $3000 to replace a battery, people would choose the former. But if you drive your car 200,000 miles and lost too much range to continue driving your car, but it only costs $3000 to get the battery to an "as new" state? Yeah, they'll spend it.
Just for some frame of reference, lots and lots of people replace internal combustion engines in their cars, either to restore a vehicle, or to upgrade it. Spoiler - they often cost more than $3000 (before factoring in labor)!
Well, obviously some people already trust electric vehicles that don't have batteries that the average consumer isn't meant to replace. So "nobody" is an exaggeration. But replaceable, modular batteries would be a nice improvement. Especially if a particular kind of battery fit in a wide range of vehicles and were available from multiple vendors. And if cars were designed to accept upgrade batteries with different electrical characteristics than the originals and have it just work.
Just for some frame of reference, lots and lots of people replace internal combustion engines in their cars, either to restore a vehicle, or to upgrade it. Spoiler - they often cost more than $3000 (before factoring in labor)!
[0] https://www.gmperformancemotor.com/category/SB.html