Firstly I am not even sure what infinityx's current status is. If they are currently Silver, I will guess that:
Indeed, but it seems that (s)he is already Gold ("revert to Silver" was mentioned, which would seem to be a stronger statement than the "go to Gold" of the title - although that wording seems unusual if you are already at Gold). This definitely changes the discussion and the OP needs to clarify that.
I'm struggling to understand why you would pay actual money to become Gold, and then start flying Delta
You know you still earn award miles, and the entire reason to be Gold is that you get benefits beyond what you are nominally paying for, but only when flying Star Alliance....
Indeed, there seems no reason to buy Tier Miles in this case. The idea of turning away to another alliance once status is "wrapped up" in one alliance is also unusual. One normally sticks with one alliance to enjoy the "fruits" of all the hard labour that went into earning that status. Unless the OP consciously wants to build up status in a second alliance - and has a realistic prospect of doing so - there is no real reason to run to Delta.
"I now have Star Alliance Gold status - so I'll spend the next few weeks flying Delta" doesn't make a whole lot of sense, without further context...talking about a "black hole" or implying that Tier Miles are "wasted" implies that the only purpose of flying is to
earn status, and that if you are simply
enjoying status, then the trip is wasted (as you should be "earning" somewhere else, where you don't have status, and therefore can't enjoy status!)