Commercial disks are pretty durable, as you say (unless exposed to weather, then they fall apart fairly quick). The only commercial disk I've seen fail were bad out of the box. But burnables, not so much. Mine have done well (my oldest ones are still readable) but I lived in the desert. Dampness and CDRs do not play well together, as they're not completely sealed around the edges, so I'm not surprised by tales of woe.
I still use CDRs and DVDRs for sneakernet to the DOS machine that doesn't speak network or USB, and occasionally for a specific type of backup (movie or album) but no longer routinely use them for system backup. I can get a whole stack of DVDs on a single 128GB flash drive (not to mention backup is much faster and needs far less babysitting), and per the torture tests I've read about, flash drives beat everything else for durability (retaining data through all manner of abuse; one even partially survived being shot).
And until recently I was still using them for live CDs for testing OS distros, but along came that bootable-flash-drive app and now I have 40+ distros on a single flash stick, plus a place to save files convenient to whatever I'm testing.
I never did acquire a Blu-Ray, tho I suppose now that prices have gotten sane I'll pick one up just so I have it if I need one. Which might be never at the present rate (I don't buy BR movies, so what is it good for? burned BR are reputed very unreliable, failing in as little as six months.)