I've repaired cars that have had the same spark plugs in the cars engine for 300,000 miles so yes it's possible for spark plugs to last 200,000 miles.
But even though the spark plugs will last 200,000 miles the engines performance will suffer as a result because as the spark plugs stay in the engine longer the gap on the spark plug opens up.
This is because as the spark plugs do there job the electrode wears down overtime and after 100,000 miles it's a good idea to replace the spark plugs to keep your engine running smoothly.
If you don't replace your spark plugs every 1000,000 to 150,000 miles then your engine may lose power, have poor acceleration, be hard to start, the engine may stall, your engine will likely misfire under load etc.
I've always replaced my spark plugs every 100,000 miles which is a good idea as they don't cost much and for me I only spend at most $25.00 for a set of spark plugs and my engine runs much better as a result and I save gas as well.
When spark plugs are not working properly your engines fuel mileage will also suffer as well.