Because that's exactly what he did, nobody in their right mind is going to leave their one source of money open to being completely demolished in one single move. Precautions don't need something to exist to be taken, that's what the "pre" part means, precaution quite literally means a measure taken in advance to prevent something from happening, in advance meaning before it happens. There is no claim, but there is a major risk for one. He didn't hide or completely stop this game, hence the "on hold" tag, he's been prioritizing the other version that won't get him claimed. He has other options, but those options are not feasible exactly BECAUSE this game has a "large fan base." Like any game with a single source of income and a large fan base, moving is extremely risky in that he risks losing A LOT of that fan base. There are many on Patreon in general who will not move away from Patreon, so if a developer they support moves, the supporters who won't move drop support never to support that game again. There is no "eternal on hold" status, the "on hold" tag doesn't last forever, it was never meant to. It is removed in one of two cases, either the game it is on starts development again or the developer stops communicating entirely for at least three months, not stopping communicating about this game entirely, it means they stop communicating at all about game development. No, only the "abandoned" tag shouts abandoned, as it is designed to do.
I am curious, though, you yourself have claimed that this game is dead, why not act like it is and move to another game? Why would you stick around a 'dead' game for so long when you could be enjoying one that isn't 'dead' to you? Most people would have left for another game immediately upon seeing the 'on hold' or 'abandoned' tag.