Correct.
First explain to us why God can't just tell everyone the same thing at the same time.
Even if God did, what makes you think people would believe anyway? How can God tell eveyone the same thing at the same time anyway? The Old and New Testament prophets used the terminology available to them at the time to prophesy. It isn't like God would tell a prophet that a nuclear weapon would detonate in 1945. If he did, then no faith would be required to believe rendering faith in the creator, and prophecy, useless.
Why is He limited to the ancient method of telling one guy and expecting the rest of us to pick the one true prophet out of the forest of false ones.
Because the bible is an ancient book! There are 12 minor prophets and four major prophets in the bible, and all of them are TRUE prophets, regardless of what you think. Prophets were also mentioned in the first century Didache, which means that they were still "in use" after 70 AD, but later became, 'obsolete.' There are no longer any prophets. All prophecy's have been given. The average Christian tends to associate 'prophets' with people who predict the future, but that's not always so. They also associate the gift of 'prophecy' with prophets, but that too is 'not so.'
Then we can discuss what you think God meant by whatever He said to whoever you think is the true prophet.
Muslim's believe that "the Prophet like unto Moses" is Muhammad. We as Christians know that it's Jesus making Islamic prophecy FALSE! Pick a prophecy, but I doubt that'll get anywhere since your an unbeliever.