First, hardware has improved consistently, outpacing any need for optimal software. Second, the end user does not know what they really want from software until it is provided to them, so most people will easily put up with slow, laggy and buggy software until there is a competitor that can provide a better experience. In other words, if companies can make money from making bad software, they will, and this is often what happens because most people don't know any different and also hardware becomes more and more powerful which alleviates and masks the defects in software.
I think there is also another big factor, which is that businesses prefer to scale by adding more people, rather than by making better software. Because they want to scale along human engineers, they tend to prefer low-tier software that is easy to pick up by the masses, rather than the high-level specialized software that is a hard skill to acquire. This is understandable, but is also the reason why software is so slow in advancing forward compared to hardware (and by the same token, hardware engineers require more specialization).
I'm sorry but I don't buy it.
I've been way too close way too often with lisp and Haskell or many other niches (I know well both Racket/Scheme and Haskell btw) the people that care that much about this correct and reliable and extensible software care about the code more than they care about the products.
That's why the languages that breed creativity and stress correctness have very little, if any, killer software to show when PHP/Java has tons of it.