It's really frustrating to feel like you're missing out conferences, but as others have said, it's probably not something to worry about.
One thing you could do, though, is have a scan through of the programme and if there are any talks you're really interested in or relevant to your work, you could always consider emailing the speaker and asking if they would be willing to share their abstract/presentation/summary of key points? Approach with caution of course as people can be very protective of their work for obvious and understandable reasons, but if they're presenting at a conference, then by implication they are making some of that research available anyway. That way, you might not have to miss out on everything, and you could have the opportunity to impress an academic by showing them how interested you are in their research. Networking doesn't have to be done face-to-face...