When it incurs relatively extreme costs? i.e. much higher price, multiple delayed launches, low number of units at launch, all a direct result of BR.
I'll give you the low number of units at launch - the 'much higher price' though is not only due to the inclusion of BR, but because of what's included in the entire package and its perceived value on the market (that includes CELL, the HDMI interface, BluRay, the built-in HD etc). If anything, BR's inclusion helps differenciate their product over the competition. If they follow the competition and offer nothing but a different brandname, it's called copying, yet adding functions that could differenciate their product even further (though at a drawback of selling at a higher price) is a negative?
Besides, the higher price isn't all together because of BR in the first place - it's also partly because of their change in strategy in making less money on add-ons and making the PS3 a more open platform - something, that on the other side of the fence, Microsoft is making you pay for, by charging horrendous prices on accessories. I really don't see a big difference in paying more for a product initially, than paying less at first and making it up as you buy into accessories/upgrades or live content. Yes, PS3 ends up being slightly more expensive, but the difference levels out a bit once you look at the big picture and notice the two different approaches their taking.
As for multiple delayed launches:
I really don't think the delayed launch is a direct result of the inclusion of BluRay - when you look at the way PS2 is still slaughtering the competition, one year after the launch of the 'early' Xbox360, launching any sooner [Spring 2006] would have been a bad idea. Especially when key features such as a built in HD, HDMI ports and BR would have had to be canceled.
Also, the high price of BR is one that will come down quick as more are produced. Once prices come down, so will the price of the PS3. Assuming BR will remain the expensive feature throughout its lifecycle is not very accurate. The built-in HD will take that spot, for sure.