Out of curiousity, when you used the diamond paddle which face of the carbide did you try to touch up? I ask because if you sharpened it incorrectly then you may have made matters worse rather than better. You want to dress the broad face of the carbide that extends out from the shaft (and not the outermost edge that forms the perimeter). It is also very important to always take an absolutely identical amount off of each carbide insert when sharpening a bit as they spin at extremely high RPMs and any imbalance will cause handling issues and excess wear in router's bearing as well as excess runout. That said, after only a few dozen feet of milling it seems very unlikely that your bit would benefit from touchup dressing of the carbide unless something has happened in the interim to damage the carbide as most of those woods, with the exception of Wenge, are not especially tough on edges (certainly not compared to some I have tackled, though some do exhibit higher than average wear).
Hard brittle woods like Wenge and Purpleheart (as another example) can be very challenging to work with a router as they are prone to catching the bit and shattering explosively during routing as a result of their interlocking grain if you do not tackle them by taking only very shallow bites off with each pass (I have occasionally had to limit such to as little as 1/32 to 1/16" depth per pass to avoid catching the grain and shattering the piece). Trying to take a full depth cut with such woods can be a recipe for disaster, it also sometimes helps to slow down the router a bit so that you can also feed more slowly without unwanted burning or burnishing of the wood. This will also make your router much easier to control with such woods since it is far less likely to experience kickback when shallow passes are made in difficult woods.
For a bit to be handling as badly as you say even in better behaved woods after just a few (dozen?) linear feet would tend to require that visible chunks of carbide actually be missing (use a magnifying lens) form the cutting edge, which can happen if the carbide has ever collided with another hard surface (such as metal or concrete) or been dropped as carbide is extremely hard and long wearing but also exceedingly brittle if impacted.
You do not say how experienced a router operator you are, but , n the event that you are new to the router, be very careful not to attempt climb cutting with a router bit until you truly know what to expect and how to control such as such is very unstable since the bit will attempt to self feed during climb cutting. Under normal circumstances you want to be feeding the workpiece against the bits direction of rotation rather than with that rotation to avoid the uncontrollability associated with climb cutting. It is not uncommon for newcomers to try to route a piece in the wrong direction, especially when routing freehand where the direction changes depending upon whether you are routing the exterior perimeter or along the interior of the piece.
Otherwise, one will typically get about 10-20x more linear feet of routing out of a carbide bit versus a traditional HSS bit. But it is impossible to say exactly how man feet you will get as it depends upon the quality and thickness of the carbide used, the manner in which the bits are cared for (such as protecting them from contacting other hard surfaces or bits and chipping them), the sorts of materials you route and how much silica content there is in the woods you try to route (some exotic woods can be almost like routing sand paper if they are hard with high silica content). That said, a decent quality carbide bit that is well cared for can typically mill quite a few linear feet of most hardwoods, including exotics, before it is in need of sharpening or replacement. But that same bit, if poorly cared for, may give out before the first edge is ever milled -- so a lot depends upon circumstances.
Did the bit ever route edges well? If so then it is possible it has been damaged in handling or use since then. If not, then it is possible, as with most things, for a bad bit to get through QC where only representative samples are thoroughly tested and inspected. I have never had any issues with Whiteside router bits over the years, but all manufacturers can have defects if the bit never performed properly.
That is a fair bit of ground covered, but hopefully you might find something useful buried in the above. In the meantime, be safe but do not give up as you will get it figured out if you keep at it.
