The examples I gave tend to indicate otherwise, and I purposely didn't include BD DL because of the price and failure rate. All one needs to do is buy single layer BDs of a great brand like Verbatim, and suddenly what you're referring to does not apply.
The real crime here is not BD DL pricing, or even failure rate. Clearly there aren't enough people investing in them for price and QC to be good yet. It's the fact that DVD media is priced higher per GB than even the best brand BD single layer, despite still being a more widely used format.
You also really should have indicated what brand and type of BDs you had fail before implying they're problematic in general. Even regular DVD media customers know discs can vary somewhat in quality by brand and type.
And the quality and age of the drive can factor in too. I've had DVD drives that stop writing well before they stop reading, and even one, which was a popular brand and model, that was DOA.
Yet you as well don't mention brand or type, what drive they were burned with, it's age and condition, etc, or how you stored the discs for that matter. UV exposure? Where were you storing them, on your car dash?
The people that start referring to discs as coasters often don't treat them very well. These are the people that are better off with Steam and HDDs. Just hope that you can predict their failure and do some mega transferring before they die. There's basically only a few things that cause premature disc failure, and what you're describing is def premature. 1) A bad burn from a crappy or aging drive, 2) poor quality media, 3) mistreatment by user.
And external HDDs can be even worse, most compromise speed and quality for price and portability. The other option is multiple 1TB internals or a few 4TB drives. Swapping 1TB drives can be a pain, while the larger capacity ones in general have less reliability, plus you have the potential to lose a HUGE amount of files.