Though the writing has been on the wall for months–if not years–Yahoo has finally been acquired. Verizon has scooped up the company to the tune of $4.8 billion. For many, this is the beginning of the end of a years-long saga to fix a seemingly broken digital media company; Verizon says it will use the new assets to build a digital media empire. For others, it’s just another chance to pile on the blame game for CEO Marissa Mayer.

All the same, there’s one big question that hasn’t quite been answered, and perhaps never will be: What exactly went wrong? While there are hundreds of facets to this broad question, there’s one big strategy Mayer opted to take as chief executive: acquisitions. Over the course of her four-year tenure, she acquired more than 50 companies and spent more than $2 billion.

“Most mergers don’t work.”

The idea behind the slew of purchases was that this was a way to source good talent and technology. If Yahoo took up numerous good startups, it could theoretically become a haven for smart, agile techies who would further the company toward its goal of being a technology leader. This, however, is not what played out.

According to John Sullivan, a talent management consultant who advises firms on recruiting strategies, this strategy failure shouldn’t come as a huge shock. “Most mergers don’t work,” he says. Only a few big companies acquire smaller organizations successfully, and it’s a very thoughtful process. “It’s like divorced families joining,” he adds.

The big issue with Yahoo was that it simply did not have the system in place to cultivate the new talent and make them feel part of the new company. “Yahoo has a bad habit of killing the products [it buys],” Sullivan says. “It doesn’t make you feel welcome.” A few examples of the dozens of startup products Yahoo bought and then shut down include MessageMe, Vizify, and EvntLive.

Many companies are simply not good at acquiring. Sullivan used to work at Hewlett-Packard, and he noted the stifling culture that often led to unhappy new entrants. To get talent to work well under new management, they have to be enthusiastic. The new company should look exciting–a place where they can continue to do their work. By appearances, Yahoo is likely not that place. Sullivan points to Facebook, whose campus is filled with perks like “a free ice cream store.” Just the space itself, he believes, could likely energize new additions. Sullivan adds that Facebook’s ethos is designed to build and innovate new products. In contrast, Yahoo’s office and internal culture, says Sullivan, doesn’t appear (from his outsider’s perspective) to have that kind of startup excitement.

There’s another facet to this, too: The way Yahoo chose companies didn’t seem to make sense. Acquiring new businesses costs a lot of money–much more than simply bringing on new developers. Senior talent at scooped-up organizations needs to be adequately compensated. Acquirers, then, should have ways to assess whether or not the investment is sound. Facebook, explains Sullivan, has a very scientific system of choosing which companies it will bring on, quantifying every hire it makes.