How do you know that other universes don't have different laws? Can you see into them?
You can't have any number of different laws that we do not know about. This is fallacious scientific thinking. There can't exist any number of possibilities through multiverses because then no experiment or observation that we do today would be valid. It could mean that it would not be successful in another universe or it may not apply to a different universe. Then there would be no way to falsify anything.
The way to these universes is supposed to be wormholes. They are also supposed to be a way to travel through time, i.e. time is shortened by going through a wormhole. What is the evidence for these wormholes?
My take is there are other dimensions instead of multiverses. For example, we know that spacetime curves when one can travel at the speed of light and that gravity will affect it and the traveler. It may not have to be the speed of light, but a percentage. Very fast space travel could open up pathways we never were able to find. Where's the evidence? One, the shape of the universe is described in the Bible. That it is flat or thin on one side and fast expanding like a curtain, and that it has edges and that the edges curve upward. We also have the standard model of particle physics, quantum mechanics, Einstein's general and specific theories of relativity and the standard cosmological model. With mathematics, we can envision how 3-D objects would appear in the 4th dimension.
One of the pieces of evidence she mentions for multidimensions is looking for particles. If we can show that a graviton exists, then it would be evidence for multiple dimensions. The graviton exists in our world one moment and could move into a higher dimension the next.
One evidence for no multiverses
Big Bang blunder bursts the multiverse bubble
Your link is what appears to be a failed experiment. Which in no way says that multiverses are not possible. Only when we can see into other universes will we know if they all have the same laws or not.
It wasn't a failed experiment, but a mistake made in looking for gravitational waves. The galactic dust caused their readings to be incorrect. What the initial success and aftermath of BICEP2 (was not correct) showed was evolution's cosmic inflation proponents were wrong. They were all too eager to propose what you propose of having any number of different laws in other universes and that cosmic inflation backs up the Big Bang Theory. All it did was show where cosmic inflation is not found.. Even though gravitational waves were discovered after this experiment, it does not mean that the cosmic inflation theory part of the Big Bang Theory holds, too. It's like they're science-ing the sh*t out of gravitational waves so that the cosmic inflation model can be propped up.
And do you know why cosmic inflation is important? It helps explain the differences in our expanding universe. If it were not true, which it isn't, then our universe would look not as dense and similar as it expanded out from its initial "bang." It doesn't explain the clusters of our galaxies and stuff even if much of the materials in the mass can be pressed into a point of singularity. Moreover, as you know, the heat of the universe in one part of the universe being the same in other parts of the universe is what confirmed the BBT for these scientists.
"Another conundrum thrown up by the basic Big Bang theory is how to explain the relative homogeneity and evenness of the temperature of the cosmic microwave background radiation. How did large-scale structures such as galaxies and clusters of galaxies develop out of what should have been a rather boringly amorphous and featureless fireball?
This would appear to be in direct violation of the Second Law of Thermodynamics, which describes an inexorable tendency towards entropy and uniformity and away from patterns and structures. If our universe had started out completely smooth, then it should have continued that way, and the universe today would contain nothing more than thinly spread dark matter along with less than one atom per cubic metre of hydrogen and helium gas, with no sign of the texture and complexity we see around us (stars, galaxies, a multitude of elements, life)."
Cosmic Inflation - The Big Bang and the Big Crunch - The Physics of the Universe