A long time ago software was a retail business.

You'd create a box and put disks, a book, coupons in it and ship it off to distributors. They in turn would send it to retailers. Then we would run ads in monthly computer magazines that would get people to visit the retailer and hopefully buy the product. 

Each step in the process involved selling, and decisions made by the buyers as to how successful the product was going to be, initially, thus determining how much they wanted to have on hand for the first few weeks of the product's life. 

This was called the pipeline. 

It took time for product to go into the pipeline and show up on dealer's shelves.

So you had to try to build demand for the product before it shipped. Long before it shipped. Which meant going on a press tour and then starting to run ads. Ads that were wasted mostly, because the users couldn't actually buy the product yet. The ads were there to impress the reviewers and the buyers in the distribution chain, to show them how we planned to create pull for the product. 

That meant you had to show the product to reviewers long before it was ready. The "manufacturing" process for software was mostly intellectual. It took just a few weeks to actually print the books, duplicate the disks and put it all together and ship to the distributor.

This was inefficient and the system and was eventually scrapped. I doubt if there are any shrinkwrap software distributors today. 

The point: The need to show the software to reviewers before release is gone too. When you read a review of a book or a game or utility, you should be able to go get it right then. And no need to give exclusive to reviewers who are paid to do the reviews. They aren't more authoritative these days, users are clued into their conflicts, and wait to find out what other users think of the product. Bloggers are more likely to influence sales than the big name reviewers. 

It's possible that might shift over the years, as software review becomes as serious an activity as say film or TV shows. But you can only really have a useful opinion about software from using it for a period of time. Not like a movie very much. 

We still have a bunch of evolving to do here.