Yes, that's absolutely been my experience -- and even then, when it comes to the data path, you will likely find new failure modes in "tried and true" as you push it harder and longer and with the bar being set at absolute perfection. I have learned this painful lesson twice: first, with Fishworks at Sun when we turned ZFS into a storage appliance -- and we learned the painful difference between something that seems to work all of the time and something that
actually works all of the time. (2009 was a really tough year.[1]) And ZFS was fundamentally sound (and certainly had been running for years in production) before we pushed it into the broad enterprise storage substrate: the bugs that we found weren't ones of durability, but rather of deeply pathological performance. (As I was fond of saying at the time, we never lost anyone's data -- but we has some data take some very, very long vacations.) I shudder to think about building a data path on much less proven components than ZFS circa 2008, let alone building a data path seemingly in total ignorance of the mechanics -- let alone challenges -- of writing to persistent storage.
The second time I learned the painful lessons of storage was with Manta.[2] Here again, we built on ZFS and reliable, proven "tried and true" technologies like PostgreSQL and Zookeeper. And here again, we learned about really nasty, surprising failure modes at the margins.[3] These failure modes haven't led to data loss -- but when someone's data is unavailable, that is of little solace. In this regard, the data path -- the world of persistent state -- is a different world in terms of expectations for quality. That most of our domain thinks in terms of stateless apps is probably a good thing: state is a very hard thing to get right, and, in your words, tried and true absolutely beats novel and new. All of this is what makes Torus's ignorance of what comes before it so exasperating; one gets the sense that if they understood how thorny this problem actually is, they would be trying much harder to use the proven open source components out there rather than attempt to sloppily (if cheerfully) reinvent them.
[1] http://dtrace.org/blogs/bmc/2010/03/10/turning-the-corner/
[2] https://github.com/joyent/manta
[3] https://www.joyent.com/blog/manta-postmortem-7-27-2015