The weight of a tent (including ground cloth, rainfly, stakes, and ropes) may not be a concern to car campers, but backpackers, who weigh their gear in ounces, give the weight of their tent serious consideration.

Large capacity (8+ people) canvas tents with accessories could weigh upwards of 60 pounds. Several people could easily erect a canvas tent in less than 15-20 minutes. These tents are bulky, and you'll need a large trunk or a truck bed to haul them.
Large capacity (8+ people) multi-room steel frame nylon tents with accessories can weigh upwards of 45 pounds. Two or more people can easily set these up in less than 15 minutes. These are somewhat bulky tents too, and you'll need trunk space to haul them.
Middle capacity (4-6 people) single or double room aluminum frame nylon tents with accessories weigh in the range of 17 to 35 pounds. One person can probably set these up without too much difficulty in about 10 minutes. These tents pack smaller, and they'll easily fit in the trunk of your car.
To the weight-conscious backpacker, a quality 2-person backpacking tent will weigh around 5-6 pounds, and a quality solo backpacking tent may weigh only 3 pounds. One person can easily set up a backpacking tent in less than 10 minutes, and these tents stow easily anywhere.