squoosh anyone who knows me IRL would be very amused by the image of me trotting anywhere like an obedient little lamb! 
It's really not as easy as that. The majority of the weddings I've been to in the past 10-15 years, either me, DH, or one of the kids has been involved as a member of the wedding party (bridesmaid, flower girl, page boy, etc.) and those are pretty much impossible to turn down. They also eat up vast amounts of your life in dress fittings, getting shoes for kids, hotel room bookings, blah blah blah.
I don't know what your current situation is (are you married/partnered, do you have children, etc.) but it was a lot easier for me to decline invitations when I was young, free, and single, than it is now.
These days I have far more serious obligations and it's a far bigger deal to, for example, stop my children from attending a wedding when their grandparents are DESPERATE to show them off - and sometimes when it's the last event that an elderly relative on their last legs is likely to attend. There is an entire web of social obligation that you seem not to understand.
Also people often send out 'save the dates' months or even years in advance - I had one 15 months before the date. It's not very easy to come up with a convincing excuse for that far in the future.