I can't find any data on MSRP now, but back in the day it seems to me that there were storage choices that were not so cost-prohibitive for consumers.
4mm and 8mm drives with multi-gigabyte capacities that compared favorably with hard drives of the time could be had for $hundreds to $a thousand or two, with media costs in the $10-$25 per tape range. At the time, there were also MO drives that had significant capacities in similar ranges, with slightly higher media costs.
Back then, the capacity of one removable cartridge/disk was much closer to the capacity of consumer market hard drives. You might have to go through 1-4 tapes or cartridges to back up all of your data, but that meant less than $100 for each additional complete backup set.
Now current consumer drive sizes are in the multi-terabyte range, while capacities of removable storage are such that you'll need 10-15 instances of media to back up your collection, and each media item is $50-$100. I have 18TB online right now. This means with a 300GB storage capacity, I'll need 30-45 instances of blank media for a single backup set. Back in the day, I had an Archive Python autoloader that used 4 DDS tapes and had a capacity of 96GB compressed, with a total online storage capacity of something like 40GB. In short, I had _excess_ capacity for less than $100 per backup set in a single operation.
At this level, it makes much more sense to just by a pile of multi-terabyte hard drives (4TB drives are currently less than $150 street price) and use them. Faster, cheaper, and without the up-front cost of the mechanism (backup drive) to pay for.
For consumers, dedicated backup technologies seem to have gone the way of the dodo.