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Lol. Bullshit to quality plastic lenses last that long. I mean sure, if you never drop them and baby the heck out of them.
The hardest clear plastic isn't remotely close to being as hard as glass or sapphire.
As for the shatter thing, often glass lenses will have a plastic layer on the eyes side of the lenses that prevents shards. This does mean that the inside of your glasses will scratch easier than the outside, but the outside is what always gets abuse.
Not all plastics are made equal. Two different 1.5 or 1.6 index plastics from different manufacturers will have different scratch resistance as well as different levels of aberration depending on how good their materials science is.
All plastic is softer than glass, yes, which is why any plastic lens you get has a hardcoat to reduce scratching and if it is from a quality lab, a scratch/antireflective coat as well.
If you've never had plastic lenses last very long, where you are sourcing them from is using inferior quality plastics with whichever lab partner they use. That or you a) leave them in a hot car and the heat damages them b) constantly leave them lens-face down on the table
But I have had people with very stable prescriptions keep plastic lenses in good condition for 15-20 years in extreme cases.
Laminated glass treatments may be used, but because they cause problems with the cutting machinery it is far more common in optical glass lenses to see chemical or heat treating. If these are done well, they can be quite resistant to shattering. This, however, really comes down to the individual skill of the person treating your lens and I've seen enough damaged eyes to be wary of them.
Another reason many labs have moved away from mineral lenses entirely is that they shatter when being cut to shape for your glasses, posing greater risk to the one doing the edging and significantly greater cost to the lab. Depending on the complexity of prescription they may shatter up to 3 or 4 times before one cuts properly into shape.
To add onto this, if you are using progressive glasses, you are certainly getting an inferior product as no lab I'm familiar with puts their new progressive designs into mineral. The majority only have designs from 15-20 years ago with terrible intermediate segments.