First of all, it is no longer easy to produce state of the art DRAM.
Second, the memory chip vendors and, indeed, most semiconductor vendors, have existed in highly competitive markets for decades. They know how to cut costs to the bone. It is only in the last few years that two of the three memory chip vendors have made good money, Micron and Hynix. Samsung has made good money for much longer, but even they are now making record amounts, because the three of them control well over 90% of the market currently.
Will the Chinese have an easy time breaking into that market? The Big Three have the experience of the steel and solar sectors to reflect on and I am sure that they are already preparing to deal with the Chinese. Penny Pritzker warned Congress about Chinese infringements and ambitions last year and I know Japan has also been alert as they face the Toshiba situation. The Taiwan govt has filed several suits against former employees of semiconductor firms for theft of trade secrets. We know about these cases; we of course don't know about employees who may have been successful.
That said, my guess is that everyone who has valuable patents and processes is ready to file against the Chinese at the first sign of infringement. Of course, on the other hand, most of the large semiconductor have important plants in China and so are open to being pressured in one way or another.
At the end of the day, we may have to depend on two things to protect against the threat that China represents to the semiconductor sector: 1) China's ambition to be not only the wealthiest country in the world but also a true leader as opposed to rogue country that depends on theft for its success. That is a thin reed, to be sure, but related to that, we have 1a) International institutions that will pressure China in various ways to punish them if they do resort to theft to build their semiconductor sector.
And second, we must depend on the ingenuity of current semiconductor firms to continue to innovate and render the Chinese theft less useful, as they will in theory at least not be able to steal the latest chips that the companies invent. We know that the semiconductor sector has been incredibly inventive over the years competing against each other and against themselves ("Only the paranoid survive") and trust that this ingenuity will continue. Both the hard drive and the semiconductor firms have continually come up with new methods and products that have improved speed, reliability, capacity and productivity over the years. I don't think that any sector has ever matched their engineering genius and I doubt if the Chinese will find it easy to do so either. Certainly not for a number of years.