The cost of applying known and understood engineering best-practices is prohibitive.
Standards for developing secure high-integrity systems have existed for many years.
Part of the problem is the exorbitant cost of adopting those standards - both in terms of process compliance, and also in terms of the cost of developing the requisite tooling.
My side project: to develop an open-source integration of freely-available tools that helps to make it easier to apply better engineering processes out of the gate (Requirements Management, Model Based Development, Simulation, Parameter optimisation & testing) - specifically tailored to distributed sensor systems. (i.e. systems that involve both embedded sensor devices and a web-service style back-end handing data analysis and management).
I'd love to make it a full-time project.