Sorry, but this is a redacted straw man argument. No one here has suggested that a PLB "instantly breaks the second the original battery expires".

What has been suggested is that ANY electronic device is subject to failure over time. The rate of failure may be extremely low but is still finite. If my car sound system fails, it is at worst an annoyance, and will cost some money to fix. If I break my leg in a remote area and my PLB fails it could cost me my life. No amount of money can fix me being dead.

PLBs are subject to rough use in demanding conditions. They are routinely attached to life jackets and gumby suits. They are carried in very wet conditions, hot dry deserts, and extremely cold conditions. A complete and thorough systems check every 5 years (not just a battery replacement) doesn't seem like a bad idea to me for a device that my life might depend on.

It is your life and your money, and you are free to make your own choices. But you have no excuse to belittle those of us who choose to follow the manufacturers recommendations.