The dates below are the dates over which the product was actively being supported (i.e. via new software releases, in most cases it remained a sold product for a couple of years after that)
Elgar/Delius 1996 - 2007
Scarlatti 2007-2013 (still sold through 2015)
Puccini 2007-2013 (still sold through 2015)
Paganini 2007 - 2014 (still sold through 2015)
Debussy 2010 - 2018
Vivaldi 2012 - present
Rossini 2015 - present
Source: dCS website, software history
So seems that their life cycle is 8-10 years
Elgar/Delius 1996 - 2007
Scarlatti 2007-2013 (still sold through 2015)
Puccini 2007-2013 (still sold through 2015)
Paganini 2007 - 2014 (still sold through 2015)
Debussy 2010 - 2018
Vivaldi 2012 - present
Rossini 2015 - present
Source: dCS website, software history
So seems that their life cycle is 8-10 years