The Avalon also has features that are only found on the Lexus line of vehicles. Sadly it's a slow seller, and Toyota probably doesn't want to expand their line up too much since the Venza is about to debut.
In the 90s when Toyota actually had sports cars, they had 12-15 models. Today with no sports cars, they still have 16 models. I don't think Toyota intends to grow their line up but just go after markets and niches where they see a void.
The first gen SC was a break through in design and styling, even today the original SC has that timeless look and doesn't seem "old". The second gen is meh, doesn't do anything for me and I never quite liked it. Though the interior is one of the most beautiful. (Which more often than not seems to be case with Lexus, good interior with a bad exterior current GS or a good exterior but the interior is lacking, like the ES350.) The later SC430s with the LED tail lights and updated non trash can lid styled rims looked better. Until today's news, I was always under the impression the LF-A is the SC's successor... not really going to miss the SC430.