Look at at figure 9 at link.
http://focus.ti.com/pdfs/dlpdmd/133_ieeeir.pdf

Notice how lifetime is much less as temperatures rise? Now did any maker tell you to get in there and clean heatsinks and more every year or so?

So sadly, it is wear and tear and there are many studies to show how this could be a few year device. The part is replaceable but given how Ti talked it up that it would last so long, they didn't make it easy to change out.

But try again with the link at the top of this forum. Just try it.
http://forums.cnet.com/7723-13973_102-571338/samsung-forum-white-dots-appearing-on-my-hlt5075sx-xaa/?tag=contentBody;threadListing

In the CNET link I have a few other links on a source for the chip, and they have videos on how to change it out.

If Samsung will cover the chip, the labor appears to cost as much as the chip so it's a wash on costs if they do that. I'd let them replace it.
Bob