I don't know that it meant anything more than "time passes"; but the subtlety, execution, and poignancy was unparalleled in television filmmaking, I'd say.
You set it up with this full blast Malick sequence of two sisters fighting, one totally emotionally curb stomps the other and throws the tiara into a tree (an already hugely significant symbol in the series), we pull away from the tiara and it's 8 (?) years later, the hurt and pain and meanness is gone, meaningless in the face of progressing time. It's pretty much the central moment of the series, I'd say, maybe the central moment of any executed entertainment in our lifetimes. I don't know that any other television program or film has ever concerned itself as much with emotional consequence in the face of the hard truths of physics and decay and time while keeping a consistent narrative around it to maintain audience interest. Malick touches on this sort of stuff but is unable (or uninterested) in building a plot around it. This is the first time someone has had the same philosophical concerns but understands that people probably need to be entertained in the process.
The only analog to this approach creatively I'd say is David Foster Wallace.