And both of The Amazing Spider-Man films also earned more than 700 million, yet Marvel was quick to recast Spider-Man. And there's a difference between keeping Ryan Reynolds after the abomination that is Origins Wolverine in another FoX movie and keeping Ryan Reynolds to appear in a mcu franchise which have a history of rebooting Marvel characters from scratch. Hugh/Patrick also appeared in that abomination film by the way and later appeared in more foX Marvel movies.
Personally speaking, if they are gonna reboot the character, they should get someone else unless they really think Deadpool can only be played by 1 actor... yet Batman, Spider-Man, Superman and the Professor aren't.
And yes another Deadpool film, can easily guarantee them an easy 800 million. But I'm not looking at this as a strategyto easy money and if Marvel Studios/Disney always prioritize easy money then they should have released Iron Man 4/5/6 by now and not dare to make films for lesser known characters.
The ASM films were critical flops on a significant downward trend financially. Deadpool 2 made more money than 1 and both films are well regarded with a large fanbase. The only reason marvel got any part of the Spider-man franchise at all is because Sony was flailing and unpopular by themselves, so continuing any part of that ASM franchise would have made little sense.
Also, Hugh and Patrick weren't even in the same league as Reynolds when it came to being completely and totally destroyed by Origins. That movie was a fairly insignificant blip in their otherwise illustrious x-men careers. Reynolds went from one of the most hated portrayals of a comic book character in history to starring as the same character (with a completely different history) in probably one of the most profitable superhero movies in history. Which got made solely because of public demand resulting from leaked test footage that showed almost nothing other than Reynolds' acting. And fueled in large part by a highly successful marketing campaign that also relied almost entirely on Reynolds' acting. That's how much people liked his version of the character.
And continuing Iron Man just for easy money wouldn't have been as smart a play as one may think. IM2 and IM3 got controversial reception at best. Making Downey the star of the Avengers movies and letting him help other character's movies was working very well, possibly better than an IM4 would've worked, and was unquestionably cheaper and simpler to make since Downey's price has been going up and up and his contract was running out (yet couldn't be allowed to end before the big Avengers finale without risking the failure of the whole overarching story project).
Continuing Deadpool for easy money, though... Disney doesn't risk much of anything in that scenario. It's basically free money. There are lots and lots of examples in the world to show that Disney very much likes free money. Forcing him into the MCU if there's conflict would be bad, but if there's conflict he can just continue what he's doing under the fox label. If there's no serious conflict then there's absolutely no reason to even consider risking the backlash that would come from recasting what is unquestionably one of the top ten most popular superhero actors still around right now.
A 'fresh start' with this character does not actually achieve anything at all, and the character as he already exists can easily slot right into an MCU movie with no serious issues (beyond the necessary agreements about how to handle violence and profanity - an issue which always comes with the character regardless of actor). The backstory changes would not only not be a problem, they're actual fodder for the character's shtick - fodder which you can't use with a different actor without it coming across as an (inevitably unpopular) attack on Reynolds.
Keep Reynolds and you have a highly capable and popular actor who is considered synonymous with the character to draw audiences in and also reassure existing fans that any stylistic changes (which would inevitably happen to at least some extent under the MCU) have Reynolds' blessing and won't seriously damage/alter the character.
Insist on a full reboot and you have an untested actor who will automatically be saddled with the resentment of being the guy who replaced Reynolds while also simultaneously being blamed for the inevitable stylistic changes to the character, all arriving just in time to be the poster child for the also inevitable 'MCU hasn't been as good since Downey and Evans left' chorus. Who would even want that job? It's just begging to be the next Leto Joker/Affleck Batman, etc.
And what would the point of that risk even be? What does the MCU get out of a non-Reynolds Deadpool? He's never going to be the next Cap or Tony. He's not going to be 'one of the team' when the Avengers movies roll around. He's just another funny guy bouncing around other people's movies and ocassionally getting his own. As established already, the MCU doesn't need him and the character doesn't need the MCU.
Either Reynolds will continue to be Deadpool or there won't be any Deadpool for a long time. That's what it comes down to.