Schiller and Adam hit it off immediately.
It was not entirely for the official origin story of his new alter ego. The main reason he accepted the terms was that the universe was on the verge of collapse.
A universe's lifespan had limits, and the lifespan limit of the Marvel Universe did not depend on any scientific principle. It depended on only one thing: popularity.
Popular characters would never truly die. Unnamed nobodies who were shelved were no different from dead, and the highest priority was the company's survival. If the company went bankrupt because of poor comic sales and bad management, every universe would be destroyed.
As explained before, if the messily established Multiverse did not undergo a complete reboot, declining popularity was inevitable, and the universes' lifespans would rapidly shorten as well.
And Schiller's activities throughout the universes could not exactly be said to have had no impact. Leaving aside his own travels between universes, the portals opened back and forth by the Spider-Army Nick had assembled, between their home universes and the Central Universe where Schiller was located, had already drilled the walls between universes full of holes.
Some more remote universes were all right. Spider-Man coming and going alone was not much of a problem. But places like the Main Universe, which had already suffered one calamity after another, were crushed by the butterfly effect Schiller had caused.
Before Schiller brought Gray Mist into the Main Universe using a Skrull body, he had observed the Main Universe from the outside. Those who knew what it was knew it was a cosmic bubble. Those who did not might have thought a lump of coal was floating there.
The Main Universe did not merely have holes in it; rather, a bit of universe was hanging from the holes.