Of course, screen printing can achieve these matches, but it often doesn't. It comes down to the capabilities of each individual screen printer. Without constant monitoring and control throughout the process, the color difference between the first sheet and the last can be drastic. Buyers will notice this shift, and it's the reason they prefer litho. They feel more comfortable with the press proofing process and generally feel they can rely on offset printers to watch their colors more closely.
Buyers also cite registration and traps among their dislikes of the screen-printing process.
Of course, this works against screen printers as they try to achieve finer resolutions. Finishing houses I spoke to are pleased that some screen printers have made a serious effort to improve their registration, because it makes post-printing operations much easier. Obviously, this either increased the cost to the buyer or lowered the profit for the screen printer, but it didn't solve the errors or delays that occurred in finishing. I've talked about all of screen printing's disadvantages in comparison to offset. Unfortunately, from what I've seen, screen printers don't discuss this benefit enough with their clients.