200 amp at 240v is about 48 KW - I would be very surprised if you could draw that much!
Decades ago, much lower capacity service was normal; my first house was built in 1954 and I think it had 60 amp @ 240 volt service. That was not enough for everything that a typical family would have, and by the 1970's 100 amp service was normal in Canada. Since then it has escalated, and 200 amp service is typical, at least for electrically heated houses. One problem might be that the total of the all of the circuit breaker capacities in the panel must not be more than some defined multiple of the panel and service capacity, to minimize the chance of overloading the service. Since there is much more branch circuit capacity than would ever be used at once - largely to provide outlets where ever they might be needed - the numbers are large.
I agree that the residence is unlikely to ever use 200 A @ 240 V even momentarily, but some components will need to be sized for that.
Actual peak draw is an interesting question. Typical North American homes have an electric kitchen range with multiple stovetop elements plus the oven, with 50 A @ 240 V service. The clothes dryer is typically electric: 30 A @ 240 V service. Kitchens have multiple 20 A or even more 15 A circuits, to handle appliances such as toasters, kettles, and other cooking appliances. Air conditioning is common - no idea offhand what that takes, but it's significant. While modern LED lighting is no big deal, the incandescents of a few years ago can easily be a kilowatt over the whole house, and peaks can be much higher with stuff such as outside floodlights. The piles of electronics are small change compared to heat-producing appliances. The really variable part is what is plugged into outlets - maybe next to nothing, maybe multiple 1500 watt portable heaters, large woodworking power tools, and a 5 horsepower air compressor in the garage. While most people here use natural gas for both space heating and water heating if gas is available, millions of people in Canada have electric heat and even more have electric water heaters; space heating alone is over 20 kW for a typical house, and whole-house water heaters run about 6 to 9 kW. With unfortunate timing, a 20 kW peak in a home even without electric heating wouldn't be implausible.
Of course a solar user going off-grid likely won't use plain resistance electric heat (more likely would use a heat pump or another energy source), and would likely be reasonable with other loads.
