I think whilst pessimism on Sonic (and Mania's) future is second nature to a certain extent given the decade of disappointment we had to experience whilst Sega fucked up the brand and broke every single promise they repeatedly made - you have to remember that this decision to focus on retro pixel-art Sonic that is a throwback to the Genesis games did come from pretty high up hence why Mania even exists in the first place. You remember all those marketing execs talking about how Sonic moving forward would take inspiration from the Genesis games and "play like the games did in their heyday" and I even remember posting that thread here on Retro with Sega's comments and everyone had the unanimous kneejerk reaction of "like fuck it will" and everyone dismissed it as hollow intention and lo and behold, nine months or so later Mania is announced and it turns out those higher ups at Sega actually kept a promise they made for once and we got an extremely good Sonic game that echoes the classics, only held back by limited original content and a slightly rushed development schedule - but ultimately a fucking awesome game true to Sega's word. If that marketing speak is to be believed and Mania's very existence proves it should be, it does seem like Sonic had a complete re-think at Sega and Sonic Mania is representative of the new strategy they're going with and intend to continue. This is why I think Sonic Team has echoed similar comments in recent interviews - they're basically just following the higher executive orders, which if those interviews are to believed is to re-focus on classic "Genesis" Sonic and make it a mainstay for the brand. It wasn't vapid marketing speak, hollow intention and more broken promises this time, it was a stringent decision by Sega to re-purpose, re-focus and ultimately re-develop the brand, steering it in a new direction to appease the fans - which is how this Taxman and Stealth collaboration came about in the first place. Point being, Sega proved they had good intentions here, that they fully acted upon, and upon seeing Mania selling millions as a digital only release no less, receive glowing reviews and even be considered in Game of the Year awards - I think that's sufficient impetus to continue on the path they intended to trek anyway and even more so given Mania's insane success. TL/DR: Powers greater than Sonic Team demanded this, and they're very likely, upon seeing the money rolling in, to demand more of it. The optimism, in my honest opinion, is entirely warranted here.