There’s a reason Zoo Tv was indoors for the first 2 legs (US & Europe) : they weren’t sure the album was gonna be a hit. There were technical and financial issues with giant screens too.
But by the time the tour started they knew they were gonna size up and hit stadiums. If you listen to a few bootlegs of the arena tour, Bono says they’ll come back soon.
The 1993 shows were already booked before Zooropa became a full on album (not an EP).
Zooropa came out AFTER the tour was announced and booked. Zooropa songs were tested during the tour and made it permanently on the setlist very late, when U2 hit Australia & Japan.
So… all the buzz for Zoo TV came from Achtung Baby, then the tour itself. Zooropa just helped sell the last few tickets.