Sli is still not what it could be, it has made leaps in the last year or so, but I think we will start seeing major improvements in the coming 2 years
I don't believe it's the case, to me it looks like SLI is a sinking ship. Why would I want to fully upgrade for the new top high-end, when I can spend much less on a mid-class same-type older card and get a noticeable performance boost? Devs know that, and they don't do much to improve that 'buggy tech for the poor' image. It's been like this for years, it has always been 'yeah, you'll get your performance improvements...if you're lucky enough with both the product and the driver'.
Me myself - I'll never buy a SLI config again (unless I'm forced to by some evil circumstances).
Remember Voodoo 3dfx cards? Probably not many do, but that's what is going to happen with the SLI, imo.