It's funny that we have all this observational data and we keep arranging and rearranging into different models, but we always run headlong into the same problem:
Infinite regress occurs when the solution you come up with simply reintroduces the same problem you were trying to solve. The article broaches on the problem of infinite regress when it asks, "Where did the Big Bang come from?" So it posits a solution that actually reintroduces the same problem: "So where did our 'parent universe' come from?"
In truth, we've most likely reached the limits of scientific understanding. However, you can never be absolutely certain you're reached those limit so scientists feel compelled to keep hammering away...as they should.
"Many of the greatest things man has achieved are not the result of consciously directed thought, and still less the product of a deliberately coordinated effort of many individuals, but of a process in which the individual plays a part which he can never fully understand." - Friedrich Hayek