In the lead up to Metal Gear Solid 5's unveiling, the hype from fans was massive on what was being poised as a grand finale for Metal Gear Solid. At least for Hideo Kojima, who even before his controversial departure from Konami had stated the fifth entry would be his last. While it was clear to many that the game's narrative never truly reached the ending he had wanted for the series, the game was still received quite well worldwide. Then, as Kojima had hastily left or was ousted from his 20-year-long tenure at the company, Konami rubbed salt in the wound and basically killed Metal Gear Solid as a franchise.
Konami could return to its revered stealth action franchise, but that would inevitably upset basically all Metal Gear Solid fans. Metal Gear Survive left a horrible taste in gaming fans' mouths after severely altering the franchise beyond recognition. If Hideo Kojima's ousting from Konami was not enough, Metal Gear Survive was the nail in the coffin for the remaining fans. Theoretically, Konami could bring back Metal Gear in some way, but it's almost a sure fire failure for a number of reasons beyond just critical reception.
Metal Gear Solid's Abrupt End
Even though the gameplay in Metal Gear Solid 5 was widely praised, there was one particular aspect that was generally understood as unfinished or half-baked: the game's story. Kojima, being the auteur-like game director with a reputation of being a perfectionist, would've never left an unsubstantial ending in a mainline entry of his brainchild without proper reason. Regardless of the nature of his eventual departure from Konami, it's clear the ending of Metal Gear Solid 5 hastily wrapped up the game's story without Kojima's insight. Then, almost as if to burn the franchise to the ground out of spite, Konami produced and release its own Metal Gear game: Metal Gear Survive.
Predictably, Metal Gear Survive was a flop, and rightfully so. Survive was a zombie survival game based in an alternate reality of Metal Gear Solid 5, and had no relation to the overarching series by any means. The game was basically a slap in the face to Kojima, who had since left to form his own development studio to work on what would become Death Stranding. It's hard not to get the impression that Konami basically wanted the Metal Gear franchise to fade into obscurity with Survive, which by almost all accounts was not a great game. Even without the added expectation of Kojima being involved, which he was not, the game was a total grindfest that just didn't have enjoyable gameplay.
Failure is Likely For Future Metal Gear Titles
Fans of Metal Gear Solid have understandably resigned any hope of ever receiving a proper Metal Gear Solid game again. Without the series' iconic game director, the franchise practically has no legs to stand on. Especially with the context of Kojima's departure and Survive's critical failure, there's no love for Konami and certainly no love left for future Metal Gear Solid titles. That being said, the series is Konami's intellectual property, and the company may do whatever it feels with that franchise.
If Konami wishes to continue with the Metal Gear series, practically any game that's shown (Pachinko machine or not) will be met with backlash. Whether someone's the biggest Metal Gear Solid fan, or they've never played a single game in the series, a Metal Gear Solid game without Hideo Kojima is objectively doomed to fail. Hideo Kojima commands respect in the gaming industry now more than ever, and with Metal Gear Survive's scandal and failure, any game with the Metal Gear Solid name on it will be met with pure unadulterated backlash. There's just no point for Konami, a publisher with a majority of its gaming catalog filled with mobile games, arcade games, and Pachinko machines.
Konami Runs a Huge Risk In Bringing Back Metal Gear
This is a stretch, but the only possible way Konami could feasibly release a Metal Gear Solid game without being publicly lambasted is to release remasters from the franchise. Even a potential remake of the classic Metal Gear Solid games gives Konami the ability to make changes to the narrative, and that capability wouldn't sit well with fans. Taking the Metal Gear Solid franchise in any kind of new direction will be met with outcry and, at bare minimum, disappointment from fans.
Either way, Konami likely would never risk bringing back Metal Gear Solid in any fashion. There's too much financial risk to be had developing a game that has an incredibly high chance of being blacklisted immediately by the gaming community. Konami would be better off leaving the franchise to unceremoniously fade away.