Morgan Stanley CFO Ruth Porat is off to manage Google’s finances, and her new job has become a useful data point in the debate over the changes in Silicon Valley—but is it good news or bad?

The New York Times’ Neil Irwin makes the positive case: Porat’s migration—like that of her industry colleague Anthony Noto, who made the leap from Goldman Sachs to Twitter CFO, and the armies of MBAs from Harvard heading west—is good news because the best and brightest want to make their fortunes at firms that actually produce goods and services to people, rather than at financial institutions that innovate mainly by gambling with other people’s money.

But if a too-large financial sector is bad news for the economy, the financialization of its most dynamic and innovative industry isn’t a necessarily a step forward either.

Financiers won’t be pitching in on the software engineering team or the marketing department. They’ll be using financial engineering to make these companies more profitable: better managing the piles of offshore cash that tech companies garner with geographically-boundless intellectual property, and supporting the acqui-hire cycle of larger companies bringing on start-ups for their talent and new ideas.

That will make tech giants more efficient companies, but it doesn’t necessarily mean they will be better at their primary mission. Instead, it’s a sign that the tech industry is maturing, with the largest companies no longer capable of generating new products. Instead, they are becoming glorified private equity firms, competing to buy the best start-ups and manage them to success—not unlike what’s happening in the pharmaceutical industry, with its similar patent-driven culture.

Twitter, which has yet to see a profit, today announced the first investment (paywall) of its own venture capital investment fund.

Of course, this argument is somewhat overstated: Vox’s Timothy B. Lee points out that Apple has been the major large-company innovator in the last fifteen years, but while the jury is still out on its new watch (color me unimpressed) the endless parade of slightly-larger iPhones haven’t been as ground-shaking as its $30 billion stock buyback-cum-tax dodge. Android’s products have certainly improved since it was bought by Google, but that still started as an acquisition, not a skunk-works project.

Part of this trend is the natural evolution of new firms and industries toward maturity; there’s no shame in running a company that does its job well and gives its earnings back to its stockholders. But remember, the two most popular ideas in Silicon Valley are that its start-ups can create brand-new products and grow at unimaginable multiples to create massive, multibillion-dollar companies; and that massive multibillion-dollar companies aren’t nimble enough to really innovate.

In other words, news that more Americans are studying technical fields or starting new firms would be positive signs when it comes to the tech sector. News that bankers are moving in for the profit-taking doesn’t seem like a leading indicator of innovation.