Tesla is probably crunched on repairs since they have so much unfulfilled demand.
And Mercedes (and VW) has dumped poor reliability cars on the US market for two decades now. The only experience they have is marketing to stupid US buyers.
Need charging stations built, parking lots ripped up and wires ran, local grids probably need upgrades, not to mention all the kinks to still work out that make owning a corolla/camry type vehicle far cheaper for 90% of people. EV is great for people who can afford to experiment and have a spare car, but people on a budget who need something that works, which is the majority, can't go for that yet.
Generation capacity is another issue - less cost than location and if there should be more incentives. Although if we suddenly need to build lots more generation capacity in short order it will put pressure on supply chains and have a cost impact as well which will feed through.
Mercedes has been around almost 100 years. A new powertrain isn't a big deal if the processes are in place.