Let us begin by saying that there are people for which an EV is not yet a good fit. They are a minority of the population certainly, but no doubt in the millions. This group is getting smaller every year because batteries are getting better and cheaper and the charging infrastructure is getting larger and better.
Now to the questions:
1) What if you live in a very harsh winter climate area? If you do not have a heated garage, how do you expect your EV to charge, when temps are below zero?
Modern EVs, when plugged in and programmed to charge at a certain time (for the cheap late night rates) or when approaching the next charging station on your automatically preprogrammed route, will preheat the battery for improved charge rate. This is why Norway, which has cheap electricity, is almost all EVs now.
2) How about taking an "extended drive" vacation? Most EVs will NOT go more than 350 miles without needing a full charge. Thus a night in a hotel/motel that offers charging stations overnight. How many are those are out there?
When going on a long trip the usual procedure is to go from, say 10% charge to 80 to 90% charge. There are two reasons: With certain battery types it extends life beyond 500,000 miles, Charge rate slows down past 80 or 90%. So you drive 200-250 miles, plug in, take a leak and get a coffee/lunch and a half hour later drive on. The latest batteries out of the lab take less than 15 minutes though.
3) What if you live in Florida, where the salt air and/or salt water can effect the batteries?
Batteries are sealed. Salt air has no effect. There have been a few cases of cars being submerged in salt water because of hurricanes. The batteries weren't happy, but then neither was the rest of the car.
4) How much is a replacement set of batteries?
Why would you replace a battery? Modern EVs have batteries that will outlast the vehicle. Some early EVs, notably the Leaf, didn't control the battery temperature with a heat/cool system and they definitely lost notable range. In fact if you need a city car with only 30 or 40 miles of range, a used Leaf can be a good deal. Got a 10 mile commute? Or just need a car for picking up the groceries? You can get a good one for $3-4,000 and you can charge it completely overnight with a regular 120 VAC outlet.
The Tesla Model 3 with Standard or Mid-Range Battery warranty is 8 years or 100,000 miles (160,000 km), whichever comes first, with minimum 70% retention of Battery capacity* over the warranty period. But the batteries don't just fail, they slowly lose range. I hope this image comes through.
So early on there is about a 5% drop in capacity and then you lose about 2% per 100,000 km or 62,000 miles.