Old L lenses that are still in production

[Dug]

2004 EF 28-300mm f/3.5-5.6L IS USM
- In 2010 Nikon came out with an equivalent that is half the weight and price.

I never understood why Canon made an L build super zoom in the first place.
It must still sell in sufficient numbers to make it production viable, will not surprise me when it drops out of the range though.

Why have you listed the 1995 EF 70-200mm f/2.8L USM a second time if you consider Williams suggestions having been updated ?

I consider the 2006 EF 70-200mm f/4L IS USM to be an update to the EF 70-200mm f/4L USM
It would be no loss to the range to drop the non IS version, except for the budget conscious it is such a good lens for the money.

I'm sure each of these older lenses has its own case to answer why it remains in the line up unchanged.

None of the primes mentioned are particularly fast compared to their premium zoom equivalent.
That makes it more difficult for them to compete with these zooms, where as primes that are faster can and people will pay the extra for them.

As Brian has said, no longer are the best zooms that far behind primes for IQ. The more limited run numbers of the primes listed here if they had a complete redesign and/or IS added would have to compete with their premium zoom equivalent
and at the same time still be a worth while amount sharper and a worth while amount cheaper to offset the zooms convenience.

It is an interesting state of play that these primes continue to be made unchanged.
Updating them is probably commercially unviable with zooms as their competition, but it would leave a hole for many to remove them since they are still very good lenses if not the best they could be.

I don't see them being phased out in a hurry, or Canon seeing any great threat to their bottom line with newer alternatives from the competition.