I don't think this makes you a bad parent at all. It sounds like you have given your kids a firm foundation, which has allowed them to flourish. That's what being a parent is about, IMO, regardless of how often you travel with or without the kids.

It sounds like you guys are/were in a position not only to travel but to have people watch your kids. I wish we had that! My mom worked full-time until about 3 years ago, and then she was diagnosed with breast cancer about 15 months ago, so watching my kids while I went on vacation wasn't on her radar and I certainly don't blame her. DH used vacation time to stay home with the kids so that I could visit my mom after her lumpectomy. OH, so technically I have been away from my kids a few nights... but it certainly wasn't a "vacation" and DH wasn't there so I didn't think about it when I first replied to this thread.
And we were barely making ends meet until 2 years ago cuz DH was in grad school and then did post-doc work for 5 years; he's only had a "real" job lol for about 2 years.