I can see someone paying $2800 for a band that they absolutely love and the tickets package includes things like side-show seating (above the guitar pit or monitor world), a meet & greet, private bar, etc. It definitely seems like a ridiculous price in and of itself but people have spent way more money on way more frivolous things, and these "experience packages" seem to be one way modern music artists keep their bottom line in the black as EVERYTHING has gotten more expensive these days.
As far as comparing it to my next bass being too expensive…eh, maybe. My #1 is a custom Sadowsky prototype that's become my main bass by far (until my next custom gets here, maybe next month) and it was WAY more expensive than the Pearl Jam tickets that the OP mentioned.
However, I'm making some money playing that Sadowsky and have changed my strategy for instruments from collecting a lot of them to slimming down my stable of basses to ones that I really love and play rather than having a bunch that are cool or a great deal yet I never take to shows (though there are exceptions for instruments I have sentimental attachments to or ones that would be impossible to replace down the road).
Before I quit drinking and smoking I sat down and added up how much money I thought I'd spent on alcohol and tobacco from when I started partaking to present, and the "conservative estimate" was so shocking that it's kept me from ever feeling bad about spending money on stuff I love and use regularly such as basses & music equipment, upgrades to my Jeep, shooting sports, international travel, etc. I guess perspective becomes important when one wants or has to justify big expenditures.
