I think the concern here comes from a long history of his, and other, companies being forced to upgrade as major versions are released. Your mind should rest at ease that as long as Perl5 is a viable language it will be supported. One of Open Source Development's major business advantages is that upgrades are hardly ever forced. When they are it is typicaly with good reason such as security and/or stability.
A prolific example is the Apache project. They released version 2 a long time ago, but version 1 is so good that it continues to be supported despite the fact that the core developers poured their hearts into version 2 and really would like to see folks upgrade.
Your business benefit is the fact that Perl5 will be around, and supported, for a long, long time with no pressure to upgrade because your vendor's annual profits have to rise by 20%. You will upgrade when it is right for YOUR business.