Well, lets entertain this idea for a minute and see where it takes us.
First understand that the Ludicrous upgrade is only available on the Performance Model S/X which is $99k/$104k to start. There are two possible upsells here, from TM3 to Model S, or from a more basic grade of S to an upgraded Model S.
There are very few people who set out to buy a $35k car and then consider the TCO of the TM3 as comparable and decide to go for it. I think the hypothetical TM3 shopper being upsold to a $99k S to get free Ludi is basically non-existant. Upselling AWD or maybe Model 3 Performance, but not a Performance S.
Now, someone setting out to buy a $78k Model S, and deciding to upgrade to a $99k Model S is conceivable. Getting the Ludicrous option thrown in maybe even makes that likely.
So what's the profit impact to Tesla for selling a baseline Model S for $78k with no discount, versus a Model S Performance with a Free Ludicrous upgrade?
Gross margin of the S is ~30%. For giggles I'll assume gross margin of the Ludicrous upgrade is 50%. The hypothetical customer taking advantage of this offer is spending $99k and earning Tesla a profit of $19,700 ($29,700 - $10,000) versus without the offer getting a $78k Model S and earning Tesla $23,400.
Lastly there is the theory that an existing Model S/X owner decides to buy a new Model S/X because now they can get a Ludi upgrade. Well, you probably don't know that Tesla already lets current owners upgrade their existing Model S/X with Ludi aftermarket for $7,500. You can even upgrade your battery for $20,000.
I'd say this alternative view is bunk. Tesla grows by selling to new owners, and has said they design their cars with 1,000,000 miles in mind. Tesla goes further than any auto manufacturer in history to maintain the value of their existing owners' investment through constant OTA upgrades, even including increasing motor output, decreasing braking distance, and they have a system design geared toward field upgradable hardware including batteries and autopilot hardware.
When was the last time you walked into a dealer with your late-model car and they had a list of upgrades they could sell you for it, to bring it inline with the same car on the showroom floor? Tesla has been doing this with their Model S at various times throughout its history.
Their success is not tied to existing owners replacing their Tesla with a new one. It's actually quite the opposite. Part of Tesla's core value proposition is that every owner should feel like they are driving the latest and greatest, and their incentive is aligned to keep you driving it as long as possible. It's part of why they don't have model years in the first place.