Most of the tedious formatting requirements do not match what the final typeset article looks like. The requirements are instead theoretically to benefit peer reviewers, e.g., by having double-spaced lines so they can write their comments on the paper copy that was mailed to them back when the submission guidelines were written in the 1950s.

The smarter journals have started accepting submissions in any format on the first round, and then only require enough formatting for the typesetters to do their job.

...really? (Incredulous, not doubtful.)

For my area, everybody uses LaTeX styles that more or less produce PDFs identical to the final versions published in proceedings. Or, at least, it's always looked close enough to me that I haven't noticed any significant differences, other than some additional information in the margins.