The low-hanging fruit have been picked over. The easy wins of SaaS and consumer web tech have been won already, but they still have an obligation to generate the same levels of profit (have you ever seen a company gracefully shrink with its industry, especially a financialised company?), so they will start to both go for niches, and go for exploitation. Growth is always most rapid at the introduction of a new industry, and if you're a hypercapitalist (as VCs tend to be) you're going to be under pressure to see continued profit levels long after the industry can sustain them healthily.