This question from a top executive at one of the large software companies in the world is an important one. The answer is rooted in an article I wrote a long time ago, called the evolution of evolution.
You see, software development is the creation of algorithms that grow larger and expand over time, similar to the roots of a tree as the tree ages. From the initial idea, the need for more functionality, more integration, bug fixing, and better scalability expands the branches and, thus, expands the structure in need of maintenance.
What started as a relativity confined idea, kicked into gear by the immediacy of exponential internet adoption rates, suddenly grows into a massive operation. Maintaining the quality of this ever-expanding operation is a massive challenge—the rapid expansion of the root structure inducing a dramatic increase in cost.
All software companies face this problem, especially because of their fragmented dependencies on other technologies outside their realm of control, courtesy of open-source software development paradigms promising to expedite rollout, compliance, and reduction in development costs. They don’t.
They make platforms more dependent on slow to respond and slow to expand public development efforts from the start designed to appease a wide array of applications. They also make platforms much more vulnerable to security breaches, as the programming public anywhere can now discover and take advantage of gaping loopholes in algorithms. Hence the excessive growth in software security companies making up for the false promises, and filling the holes of open-source affiliations.
The answer to systemically reducing software development costs is relatively simple. In lamens terms, to frequently plant a new tree where the old one stood. To whenever possible reinvent the normalization of the offering upstream, thereby trashing the prior development and exorbitant costs of runaway downstream.
Ergo, to reduce your development costs, you must reinvent continually around a new normalization of truth and become the owner of the stack you and only you can control—the opposite of what is practiced so widely today.