changed my ims bearing. was like new

[Gelbster]

The causes and modes of failure of the M96 IMSB are many and even now , not completely understood.
The responses to the risk of IMSB failure vary from preemptive upgrades that will easily outlast the engine to prayer.
It all depends if you want to rely on Engineering or hope. You are correct , many of the 'hope' guys have been lucky.
As for the "I replaced my IMSB and then the engine failed" cases - there are 14 pages of Instructions mostly single spaced with revisions and updates- that the average DIY guy seldom finds or follows to the letter. If these specific Instructions are ignored ,yes the new IMSB may fail,possibly with collateral damage. And then there are the essential ,expensive Special Tools that may not have been used ?
IMHO the main advantage of a pre-emptive IMSB replacement is that it is more likely you pass the pre-qualification test. Which is another problem - many IMSB replacements do not mention following the pre-qualification checks. So those guys are in the 'hope' category also.
So your cars with original and perfect IMSB's are gems !