Rather than think of their primary business as securing digital assets, think of their primary business as convincing people that a perpetual money machine in the shape of a video game is possible. The valuable digital assets are just a narrative tool — and so it follows that they wouldn’t have the expertise in securing digital assets.
Nobody capable of building a secure system for digital assets would waste their time working for a company like Axie, after all, the entire premise of their business is flawed so people with the critical thinking skills necessary to build a secure system would apply that critical thinking to the viability of the company — and, of course, conclude it’s destined for failure and not hitch their wagon to it.