From an environmental perspective you are probably right. One of the nice things is that glyphosate, unlike most herbicides, is broken down quickly by soil bacteria.

The longer term issue is evolved weed resistance due to its over use with "Roundup Ready" crops and for end of the season dry down.

I think the fears about glyphosate resistance owes too much to antibiotic resistance, but I am not really sure it makes sense.

I suppose there's some regimen where you carefully monitor every plant sprayed with a weedkiller is monitored for survival and killed with fire if it survives, or some other extreme measure to be sure there are no survivors to develop resistance, but realistically the weeds are going to develop resistances over time.

And ... so what? The value of a weedkiller like glyphosate is using it to kill a lot of weeds in wide-scale agriculture. If the weeds develop a resistance to it, and we stop using it because it's no longer effective, we're not really in a worse position than if we never used it at all. It's not like there are some really bad weeds we need to save it to be able to combat.