I read articles like this as saying "reached their limits [as we currently understand them]." Sometimes we learn we were mistaken and more is possible but it's

I read articles like this as saying "reached their limits [as we currently understand them]." Sometimes we learn we were mistaken and more is possible but it's not reliable and, crucially, when it happens it happens in unexpected ways. The process of talking about when (and why) techniques have hit their useful limits is often key to unearthing the next step.