No, not really.
In short, SPSF was a short-term-gain, long-term-loss proposition for shippers, both railroads and the country's infrastructure, as there is little real benefit to merge the two lines. The combined would add Southern Pacific's dominance in California to Santa Fe's huge network in the Midwest, but it would all but eliminate competition in the Chicago-Los Angeles corridor, as the only competitor (and it would be a distant one) would be Union Pacific, and that would be on UP's already-congested Omaha-Salt Lake City Overland Route. SPSF would be in a pretty much monopolistic position, in addition to substantially reducing rail competition in Texas, New Mexico, Oklahoma, Arkansas and Louisiana. There was savings to be had, but at the cost of what would certainly have been big problems later on.
If it had happened, the plans for the merger including abandoning a bunch of sections of SP's Sunset Route and the ATSF Transcon, which would have been fine in the 1980s but would become a huge problem in the 1990s and 2000s - indeed, the lines through Cajon Pass today is a major bottleneck for both BNSF and UP, and it would be much worse if there was only one route as what would have happened here, with SPSF and UP all looking for capacity on the same single route.