It's a very personal choice on how much something is worth to you, but I think the killer here is that you can likely get most or all of the benefits of platinum in other ways and indeed acquire platinum status itself in other ways (challenge on AA or US, focus your flying on OW and wait till you've flown enough etc.).

I would be inclined to get a clear picture on "how else would I gain platinum during the year, including possibly by spending up to ~$1000 extra to do so" as well as a clear "what would I do if I stayed on Gold". And then just choose: once you know what an apple and an orange tastes like and costs you don't try and work out which is better in some objective way: you just pick one.