Every scientist and every peer-reviewed scholarly publication I've read in the past ten years asserts that spacetime is no longer in question.
Prior to 1970, astronomers knew the universe had a beginning but understood little about exactly how the universe got its start. Then two physicists, Stephen Hawking and Roger Penrose, produced the first spacetime theorems of general relativity. Their theorem proved, within the framework of classical general relativity, that if the universe contains mass and if the equations of general relativity reliably describe the universe's dynamics, then its space and time dimensions must have had a beginning that coincides with the universe's origin. The proof that time was created has enormous philosophical implications.
Within the universe, time is the dimension in which cause-and-effect relationships occur. Effects follow their causes. So the beginning of cosmic time implies that an Agent (cause) outside the universe's spacetime dimensions is responsible for bringing into existence the space, time, matter, and energy (effects) astronomers observe.
Now a whole family of space-time theorems exists. These theorems apply to any expanding universe model wherein physical life could possibly exist. Specifically, they are applicable for all life-permitting inflationary hot big bang cosmic models as well as all life-suitable quantum gravity models.
(In inflationary hot big bang models, the effect of general relativity is augmented by a "scalar field" that stretched the universe at many times the velocity of light during a brief period when the universe was younger than a quadrillionth of a quadrillionth of a second.)
Cosmologists don't doubt that the universe contains mass. Neither do most people. However, at the time the first space-time theorem of general relativity was published, astronomers had performed only three independent tests of its reliability. And they had determined to only 1 percent precision that general relativity reliably describes the dynamics of the universe.
Today, astronomers have performed more than a dozen independent tests of general relativity and have confirmed the reliability of general relativity to describe the dynamics of the universe to better than 0.000000000001 percent precision.
Roger Penrose, coauthor of the first space-time theorem, said, "This makes Einstein's general relativity, in this particular sense, the most accurately tested theory known to science" -Roger Penrose, Shadows of the Mind (New York: Oxford University Press, 1994), 230.
The thoroughness of testing and the precision of results combined with the breadth of the space-time theorems leave no reasonable basis for doubting that a causal Agent outside space and time brought the universe of space, time, matter, and energy into existence.
That said, Craig's objections are worth a serious look as a response to infinite, dynamic universes. Scientists typically regard infinities as a sign that they have entered a region where their theories are no longer valid. So, there may be good philosophical reasons to reject the notion that we live in a spatially infinite universe. Even so, the issue of the actual spatial extent of our universe still remains.