Book about those left behind in an over-populated earth that was considered dying and was abandoned

Question

The story starts with a man living in modern civilization as we are about to embark and leave the dying world and there are more people on the planet than seats on the fleet leaving for the new home world. For the main character, he was not selected and was left behind by everyone he knew, including his family.

He ended up out on a farm trying to grow food to eat and eventually was able to grow food. People showed up that eventually became his new family/community. They all had to re-learn tried and true methods to sustain themselves without modern infrastructure, such as horses and ploughs etc.

He fell in love with a woman that ended up on the farm and lived out the rest of his life with the end result being grateful he was left behind. (I believe the woman showed up was in average shape but as she worked hard and became fit and lean and an attraction grew between the 2 grew from it... at least that is how I remember how the author wrote it.) The things he now treasured and learned would not had been possible if he left with everyone else and I believe that was the message behind the book.

I want to say the name had "world" in the title and the version I read the book had red letters with a white cover...

Answer 1

This sounds like Piers Anthony's But What of Earth?, admittedly more famous for Anthony republishing it with lengthy endnotes complaining about the original published edition.

From this review:

But What of Earth? is a typical and competent old science fiction novel, a story of an overpopulated and polluted Earth that's been abandoned by the mass of humanity left behind when interstellar colonization becomes possible; the novel is set in the remnants of the civilization left behind, and follows their story of redevelopment.

I do remember the romance, with another aspect that stuck out in my memories being the protagonist's description of creating rain collection mechanisms, including a black solar tank so he could have hot water for showers.

Quickly rereading the archive.org copy, I found a passage talking about the woman having grown more attractive due to hard work on the farm.

Brand had had excellent foresight. Too bad Scot hadn't understood. Maybe the man would know about a more practical detail. "Lucy didn't look this way before. How did she change?"

"Good clean livin'," Brand opined. "Clears up the skin, takes off flab, builds muscle. Same's happened to you."

The other thing which I had forgotten, but remember now that I see references to it, is that the woman turns out to have been the one who stole the protagonist's car at the beginning, causing an accident for which he was blamed, which he believed to be the reason why he wasn't picked to be able to leave Earth.