Re: "...So what are the chances that a people that had been in the area for 10,000 years only became civilized 300 years before the colonists came. They obviously got their technology and their use of language elsewhere..."
The chances are every bit as good as the chances that thirteen small agricultural settlements existing as colonies for the King of England, could successfully revolt against the world's mightiest economic and military power, and in less than 200 years achieve preeminence as the world's mightiest and wealthiest superpower.
I find most of these threads contesting "who was first" or "they couldn't have done it alone" to be "junk science", as well as "projecting one's own historical world view" into a tidy and neat conclusion based on contradictory and seemingly unrelated bits and scraps from the archaeological record.
In a very real sense, such views echo those of the "Afrocentrists", when they insist that "the Greeks couldn't have developed philosophy and arts...they stole all the pre-existent knowledge from the "Kings and Queens of an advanced Africa".
For example, a skull is dug up (usually accidentally) somewhere on the American continent which most resembles a Japanese physiology. "Aha!"..."Why this 'proves' that the "Indians" were not indigenous to America!"...
Not necessarily so!...Such a "kneejerk reaction" eliminates each and every other possibility imaginable or possible as to why such a skull appeared on the other side of the world. Perhaps long lost racial or ethnic civilizations which left no available evidence for us (or perhaps we just haven't yet dug it up) sailed the seas of the world, captured Asians as slaves, or perhaps brought a Japanese cook back home with them on their ships....Or perhaps a gigantic global volcanic or tsunamic cataclysm may have occurred, the aftermath of which was depositing just one "out of place" skull dug up by those excavating miners thousands of years later.
The world in which we live constantly yields more and more evidence which scientists have a difficult time explaining in terms of a steady time line.