A long while ago, I worked on part of a memory system that during development we knew was corrupting RAM. The amazing thing, is just how high the error rates could get before the machine would actually crash. That is largely because so much of RAM is code that doesn't get executed and data structures that are resistant to random corruption. Even actual dat corruption when it happens is frequently subtle because it flips a transaction timestamp by one digit in the midst of millions of transactions/etc, or the data is transient a video frame with a miscolored pixel, etc. Its really like playing Russian roulette with a revolver that has a few (b/m)illion chambers.
Generally by the time you see actual program crashes or notice data corruption your system is really good and screwed. That is part of why people in the know are so afraid of RAM corruption. It can be persisted and exist silently for a very long time before someone tries reading some file/transaction that was corrupted during a write years back, or the database suddenly starts crashing after it updates some index as part of a GC pass/whatever, while the actual bug/HW failure will never be reproduced.
If you luck out with reliable hardware the rate of pure bit flips from high energy particles is rather rare.
Problem is if you start having unreliable hardware it could be any component of your system. ECC memory helps track down a class of errors that could be in the ram chip, dimm, dimm socket, motherboard, CPU socket, or CPU.
My desktop cost another $100 or so because I got a E3-1230 xeon instead of the similar clocked i7. I bought it in 2015 and it's been fast, and reliable. Sure I might manage 6 month uptimes anyways, but I also might track down a dimm problem in hours instead of weeks.
Not that it happens frequently, but if it does and your application scenario is critical, how do one knows if say the corrupted data is a minor color component in an image or frame of a movie, or a variable in a spreadsheet cell buried somewhere? Would anyone notice? If a bitflip happened in a location containing the target address of a jump then the software or the OS would likely bomb immediately telling there's something wrong somewhere, but (unfortunately) there are subtle errors that can go unnoticed until it's too late. ECC is meant to protect also from those.
My PC doesn't have ECC memory and it isn't crashing and corrupting my data. I think you are vastly over exaggerating.