stroller envy
n. Feelings of envy directed at high-end baby strollers owned by other parents.
McCavanagh is one of many new parents surprised by a flood of new parental instincts, one of which is stroller envy. It is a curious affliction that makes otherwise sane and secure parents feel woefully inadequate in the presence of hefty-priced prams - the $500 Phil and Ted's e3, the $800 Bugaboo Frog, the $1,000 Stokke Xplory - and ashamed of themselves for wanting one.
—Kate M. Jackson, “Coveting thy neighbor's stroller,” The Boston Globe, October 04, 2007
When my daughter, Ava, was born two years ago, it wasn't parenthood's usual defining moments that surprised me—a duo becoming a trio; a newborn's messy anatomical bombs; the whoosh of love that makes your heart feel bigger than the Chrysler Building. Those all happened—big-time—but it was the quirkier, smaller realizations that brought home for me just how fundamentally my life had changed. The signs no one (least of all me) could have missed: …

8. "Car envy" became "stroller envy." Living in Manhattan, where cars are practically everywhere but hardly ever practical, I used to dream about getting into a convertible and hitting the road. But now that my walks through the city are done behind a stroller, my eye has wandered away from high-end automobiles and on to haut monde babymobiles. I now lust for a Zooper Rumba instead of an Alfa Romeo, a Chicco Caddy instead of a Cadillac STS.
—Joe Neumaier, “'I knew I was a dad when…',” Redbook, June 01, 2007
1992 (earliest)
The Sesame Street store tried "valet stroller parking" outside its doors a year ago at Christmas, but even then, things got crazy.

Assistant manager Joe Shapley remembers 102 strollers sitting empty one day. Even now, parents will pull up, hoist the baby and any bags into their arms, and leave the wheels at the entrance of the store with the green facade.

It's there, perhaps, that stroller envy sets in. … Parents sneak glances at stroller brands.
—Jennifer Lowe, “Stroller set rolls into malls,” Orange County Register, September 28, 1992