[Blacksheepaalredy]

I should clarify here that by "layperson" what I had in mind is someone who is still bound up to some degree with worldly and sensual pleasures. That's why I only mentioned the first two stages of enlightenment.

At the third stage (anagami) one has abandoned tanha. That means celibacy, among other things -- so although one may technically still be a layperson, the lifestyle is more similar to that of a monk's or nun's. I'm not sure what percentage of Buddhist laypeople aspire to achieving this, though I'm sure some among the more dedicated practitioners do set their sights on it. Things that are important when one is young, newly married and raising a family may become less important with time and age. Everything in its season...

As to what is a realistic goal, it still comes back to one's circumstances, commitments and priorities. This is what constitutes "unpaid karmic debt". Due to choices made in the past, one has come to a certain situation now, which presents various challenges. To use again a personal example, it would be difficult for me to go off on a six-month retreat while fulfilling my parental obligations. Who would take my kids to soccer practice or check on their homework? But through studying and practicing the dharma to the best of my ability, I am creating karmic conditions which may be conducive to progress on the path. With patience, the opportunity to go on that retreat will eventually arise.

"Debt" is a metaphor -- it's not that there's some deity that keeps a tally. Most Buddhists believe actions of body, speech and mind create conditions which eventually manifest in some sort of result.