...and in North America you lived under a bush and ate manna from heaven, is that right?
Certain people live in the lucky circumstances of great freedom combined with no responsibilities. These people tend to benefit from the efforts of others (parents who let them live at home, a working spouse/partner, a friend who lets them couch-surf indefinitely). For those who have these benefits and
no untidy encumbrances in the form of a spouse or partner, children or elderly parents (and who are additionally blessed with unlimited good health), one could indeed say "seriousness", or lack thereof, is the sole limitation of their aikido training. It's when people in this situation fail to recognize the rarity of their privilege, and judge others as if they were in similar circumstances, that the reasoning becomes absurd.
That's a pretty dismissive generalisation, Mary. I moved continents to train too, and I didn't "benefit from the efforts of others" (although I managed with the support of my significant other). I paid my own way and made my choices. If you or anyone else didn't make that move for whatever reason, that's fine, but don't belittle the efforts of those of us that did.