The thing is that Mark has always done his own thing when it comes to FNAF, even if there were always easier ways to do certain things (getting the minigame in Sister Location through the extras menu rather than constantly dying being one big example). In his UCN streams you can tell he was more frustrated than entertained, and half of that frustration came from the people in the chat, and I guarantee you majority of the people in that chat also saw UCN videos from Dawko, Razbowski, 8-Bit Ryan, CoreyxKenshin, etc... so they were giving him advice from those videos that went further and beyond where Mark was at.
Help Wanted had more updates (like the withered animatronics in FNAF2 coming back for a "Nightmare" mode), but he never went back to it, either thinking there were no more updates after the halloween update, or he was just burnt out on FNAF in general, which for Mark is rare considering the first 5 games he's always made an attempt to do the super ridiculous hard modes. With Security Breach, you could tell on his face, as soon as the comic panel ending came on, that what he saw was complete trash, even asking "did they run out of budget?" You have to ROYALLY fuck up for Mark to be dissapointed in a FNAF game and when fan games are doing a better job than your "professional" project, you need to re-think your priorities and re-evaluate your choices as a developer.