People don't care about the programming language used to write their apps?
A commenter on a previous blog posting suggested "Consumers dont care about programming languages, they just want solution" ... there is so much truth in that, and it's easy to just let that statement stand because of the truth within the statement.
We the people want good quality products, right? And I suppose it isn't important at all how those products get to us, how they're made, etc.
Speaking for myself ... maybe I'm a strange weirdo, but I care a lot about the full wholistic picture of the products and services around me, and a lot more attributes than whether the resulting product is good quality or not.
A high quality product is of course important ... But every product carries along with it a set of extraneous attributes and side effects. Such as the pollution made in the factory that produces the product, or the pollution produced by the trucks and trains etc that transport the product to the store. If you only look at the end result then it's easy to miss those other effects.
For example ... electrons are electrons, so you might wonder .. does it make any difference what kind of electric plant produced those electrons? Coal or Wind? Nuclear or Solar? See, electric production from e.g. Coal carries extraneous attributes of acid rain and extreme pollution. Electric production from nuclear material results in highly poisonous "wastes" which require 10's of thousands of years of storage before they become relatively safe.
If you only look at the end result - electrons - you'll miss the poisons spewed into the environment from the source of your electricity. And those poisons are acting to damage our health, and to skew global weather, and to cause the melting of the icecaps.
To get back to the original question ... What does it matter which programming languages were used in developing a given application?
I think I'll leave that as an exercise to the readers ...