All monsters had unique abilities, so there was a need for people with a wide variety of skills to handle them.
Thinking about it from this angle, there really might be heroes that were needed by the people, who showed up as if they were clichés in a game.
But reality was different.
The governing organizations disliked the existence of armed groups outside their control. Even setting financial concerns aside, the social status of adventurers was still low.
There were other reasons why countries didn't take in adventurers en masse. Instead of hiring permanent staff with high salaries, it was better to outsource the work to local adventurer guilds, which made more sense as a business. For companies that can operate without the adventurers guild or a nation that can clear monsters with their military, the status of adventurers were even lower.