One of the primary reasons companies don't invest more in IT is the simple fact that many of them don’t see enough of a material return on that investment (ROI). Due to a range of socio-economic issues outlined by a report from the U.S. Council of Competitiveness, not only has the economic recovery since the Great Recession been slow, actual productivity has been declining for the best part of a decade regardless of investments in IT.
Most IT budgets are a single-digit percentage of the overall revenues an organization generates, usually in the two to three percent range. Assuming most companies turn 10 percent of their revenues into actual profit after taxes, that would suggest that at least 85 percent of the revenues an organization generates gets allocated to fund things other than IT. Obviously, changing the distribution of that allocation is going to require convincing business leaders that additional investments in IT will fundamentally improve the productivity of their organizations.