I have heard that the 70s are when shu was first produced / sold on a large scale, or when the process was really ironed out*, but I have also heard from a couple of different sources (and at least one book) that some older teas have some ripe tea blended in. I don't know how that worked, or whether the process was the same, but for example, some of the early huang yin (as early as the 50s or 60s) is said to have 20% ripe tea, which matches up with what I was told by one or two other Teachat members. This book also mentions tea with some ripe content even a bit earlier, like the 40s (for example, the yangpinhao (楊聘號) cake from that time is said to have 20% ripe content).
I am definitely not in a position to say for sure, but I don't think it's quite as clear-cut as what you sometimes hear. It's possible that the process was being experimented with for a while before the 70s. Certainly the basic idea had been used for other types of hei cha for a while before this. I have another book on the way which may shed some light on this too.
I'm not sure how long people waited to consume raw pu'er back then, or how it was stored pre-1970s.
"Traditional" storage raw tea is another option if you want something to drink now. I've had some tea from the late 90s and early 00s which is fairly smooth already because it's been wet-stored for some of its life. In some cases, it needs more time to air out, but this is certainly an option if you can get it. You will still want something with some age on it, but usually the price will not be so exorbitant, and sometimes broken up / blended teas are available loose.
There are some exceptions, but for me, there's usually a limit as far as how good shu can get. That doesn't mean that I don't drink it or sometimes crave it. And, while the conventional wisdom is that ripe tea won't change much after the several years it takes for the wodui taste to die down, I have had some older (20+ year) ripe teas which are quite nice. No reason not to drink it; as others have advised, it's probably a good idea to stick to the big factories, and don't spend too much on new (produced within the last 15 years) ripe tea.
* See, for example http://en.wikipedia.org/wiki/Pu-erh_tea#Ripe_pu.27er
This same line is repeated over and over online, but I am not sure what the source is.