When you start valuing new things, then you automatically stop having time to value the things you valued before. So you stop valuing them. Because your values changed.
So let your values change. You'll be the richer in the end.
But do you want your values to change? An extreme example is drugs, if you start taking certain drugs your values will get replaced with wanting more of the drug. You-then might endorse that, you-now emphatically won't (I hope). In the GP, the key point is that you would have to sacrifice something... it's not surprising, it should be expected. The question is what, and whether you would want to.