This is a big flaw in your thinking. The republicans typically vote as a cohesive group of lemmings. Their leadership signals how they should vote and they follow. The democrats act more an independent collective of votes that happen to align on many issues, but not all.
Can you really not see it in yourself when you post things like this?
When were these chances? I don't think there have ever been 60 pro-abortion votes in the Senate.
How do you know, since, again, no one even tried?
Joe Manchin's pro-life and been in since 2010
Blanche Lincoln voted for the partial birth abortion ban
Mark Pryor voted for the partial birth abortion ban
Kent Conrad voted for the partial birth abortion ban
Byron Dorgan voted for the partial birth abortion ban
etc. etc. etc.
The cynic in me thinks that neither party wants this issue to go away because it fills voting booths.
Democrats have had multiple chances to codify it and didn't even try. They could also get some buy-in from on-the-fence people and maybe even a few very centrist Republicans in bluish states with a compromise that codifies protection for abortions in the first trimester but nope.
If Republicans really were serious about adoption as an alternative they'd make reforming and funding adoption and foster care a huge priority. They'd also entertain medicare coverage for uninsured women giving birth even if it's to be given up for adoption so as to remove the financial incentive for abortion. But nope.
Why solve a problem or find a viable compromise when the controversy gets you elected? Culture war controversies also distract from incompetence and corruption.