AMD used to be quite popular in the Athlon era, especially when Intel screwed up big time with Pentium 4 and Itanium. But, as we know, Intel recovered, then used anti-competitive tactics against AMD, and finally AMD screwed-up with its next architecture. All of these more than ensured Intel's comeback.
So I'd say wait until AMD has 50% of the market (not just the custom PC market, which AMD will probably have within 2-3 years) to feel sorry for Intel and worry about Intel dying.
Then... Core2Duo happened so fast and AMD disappeared so quickly. Felt like overnight.
No, am still worried about Intel plotting behind the scenes to undermine AMD. AMD is nowhere near the position to abuse their power and they're unlikely to be for a long time, so let's not be alarmist here.
However, I don’t think this is really a major worry, because the actual real threat is from ARM and ARM has a lot of manufacturers.