As both a computer scientist and a photographer, I can tell you that the benefits of a program like Lightroom, to me, far outweigh the risks. I've been using Lightroom since the 1.0 days because photoshop/imagej/gimp/etc were just not cutting it for me when I had 500+ images to edit in two hours or so.

I should preface by saying that I don't fear monolithic or proprietary systems, though.

It all depends on how you use the system, to me. First, I store all my photos on a Drobo, so the chances of data loss from drive death are lessened (though, of course, not eliminated). It also centralizes all the image information into one place, rather than having everything scattered all over the place. Next, for the edits, all of my final images I save out as separate, full-quality jpgs that then get uploaded to a remote server. That way, the 'best' images that I like I already have saved somewhere offsite and I don't have to worry about retaining the Lightroom editing stream.

I also rarely return to images that are more than a few months old. Once the jpgs are done and stored remotely, I just don't go back. I have all the images in raw, just in case, but it's been several years now, and I find that I just don't have the need. When I do, I find that it's better to process the image from scratch, because I now know more than I did then, and can do a better job reprocessing the image.