I would probably take delivery of the MY even if no credit. Place new order for MY if credit passes. Once received, sell existing MY. You are taking a risk on resale value plummeting more than the credit, but given MY and other Tesla wait times, you will like receive a premium if you sell the MY because they can take delivery immediately.
It's quite a gamble to take delivery of a MY, order another, and sell the original later. I too have considered it.
It's a gamble on resale value and wait times. Oh, and Rebate risks....
I think a better strategy is to place a new order. But ONLY IF you can WAIT.
The breakeven, using 11/4 pricing updates, for a base MY vehicle is about $6250 in PoS credit vs taking a base configuration MY in 2021.
Note that's a Point of Sale credit calculation, not a tax rebate. Rebates are a mess to calculate as every individual can be different.
RESALE VALUE
The current MY is going to be a poor resale candidate compared to a 4680-powered MY that will also weigh 440lbs LESS than than one delivered now.
I actually think the battery matters less than the weight reduction. Weight buys range, handling, performance - and also body panel consistency.
The megacasts the new MY uses will be lighter and more dimensionally consistent than welded stamped steel pieces, yielding a higher quality construction.
WAIT TIME
The MY wait times are going to decline quickly once Austin gets rolling by mid-year.
Yet that is predicated on 4680 battery production reaching commercially viable yields - the current 70-80% is not sustainable.
What's available for Tesla 4680 batteries are cherry-picked from test runs at Kato Road. That can't last.
The BIG REACH is what $$$ Rebate amount any Federal Legislation might settle on, AND it's Terms (PoS Credit, or Tax Rebate).
I can't imagine that the 12,500 gross amount, 8,000 Tesla amount, is going to stand.
I can see 8500 and 4500. But that's just my WAG.
Either way, it's a huge cost transfer from the Feds and expensive as hell, but the Dems can't NOT do something, so something WILL happen.
A DIFFERENT IDEA
Maybe sell your delivery position. A nominal fee of say, $1000 ??? For those that can't wait, a car NOW has value vs renting, etc.
But, that idea has social media shaming risks.....