I've been using and supporting ES (and OS lately) for well over a decade. Mostly its fine but a lot of users struggle with sizing their clusters properly (which is costly). Elasticsearch falling over is what happens when you don't do that. It scales fine until it doesn't and then you hit a brick wall and things get ugly.
Additionally, many companies learn the hard way that dynamic mapping is a bad idea because you might end up with hundreds of fields and a lot of memory overhead and garbage collection. I've fixed more than a few situations like this for clients that ended up with hundreds or thousands of fields, many shards and indices. Usually it's because they are just dumping a lot of data in there without thinking about how to optimize that for what they need.
A properly architected setup is not going to fall over randomly. But you need to know what you are doing and there are a lot of clients that I help that clearly don't have the in house expertise to do this properly and are a bit out of their depth.
Additionally, many companies learn the hard way that dynamic mapping is a bad idea because you might end up with hundreds of fields and a lot of memory overhead and garbage collection. I've fixed more than a few situations like this for clients that ended up with hundreds or thousands of fields, many shards and indices. Usually it's because they are just dumping a lot of data in there without thinking about how to optimize that for what they need.
A properly architected setup is not going to fall over randomly. But you need to know what you are doing and there are a lot of clients that I help that clearly don't have the in house expertise to do this properly and are a bit out of their depth.