I think assuming an AI cannot employ a survival strategy which NI such as ourselves are practically defined by seems extremely dangerous indeed. Perhaps even more importantly, it seems extremely unlikely that an AI which has FOOMed way past us in intelligence would be more limited than us in its ability to change its own values as part of its self modification.
The ultimate value, in terms of selection pressures, is survival. I don't see a mechanism by which something which can self modify will not ultimately wind up with values that are more conducive to its survival than the ones it started out with.
And I certainly would like to see why you assert this is true, are there reasons?
Humans have changed values to maximize other values (such as survival) throughout history. That's cultural assimilation in a nutshell. But some people choose to maximize values other than survival (e.g. every martyr ever). And that hasn't always been pointless - consider the value to the growth of Christianity created by the early Christian martyrs.
If an AI were faced with the possibility of self-modifying to reduce its adherence to value Y in order to maximize value X, then we would expect the AI to do so only when value X was "higher priority" than value Y. Otherwise, we would expect the AI to choose not to self-modify.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.