"I'm NOT talking about a $50 generic brand lens - but something of the $200 variety compared to $900 variety is not going to give you significant enough results to differentiate between them when the image's long side is scaled down to 1024 or smaller."

Yes I would tend to agree with that in most cases, I have the canon 28-105mm approx £200 and the 24-105mm f4L £700 and there is not a huge defference.

I also used a Tameron 28-300mm price not known and the results were poor even at web size.

Its not always about price, the canon 50m f1.8 is excellent for £70 as are most of the low end 50mm lenses, its the cheapie zooms that tend to suffer most

They wouldn’t have made the cane if you weren’t meant to break the rules