True. Luckily it's not required to "perfectly" reproduce the original instruments, instead it's certainly sufficient to reproduce them to an accuracy that is good enough that the difference cannot be detected by ear.
For example, if you buy 5 instruments of the same type and brand, there'll be significant variation between them. (often enough to be hearable) A digital copy that is equally close to the original as the 5 samples are to eachother, is certainly good enough.
Getting that close is still a lot of work, of course, and sampling is almost certainly going to be the easiest way of getting there.