If they (Chinese) build a 3D printer, it will probably breakdown by the time it arrives in US. On the other hand, if South Korea wants to build one, then you may have competition. But, that is years away.
You may ask why years away?
Take a look at iPhone and Samsung timeline. Apple enjoyed big margins for almost 7 years and still continues to. AAPL went from $3 to $700 so what will DDD do...go from $10 to $2000. That is fine with me. I bought DDD between $25 and $30 in the past and added more today during the early morning pullback. If market gives me another opportunity to add more, i will add more. I am not looking at the PE anymore. I am looking at the fed printing and high flier stock list. DDD is a premier high flier for next 3 years. Enjoy!