This is probably the cheaper option. I doubt they have deleted their previous releases.
My work iPhone will say up to date after being a brick for 3 months, and I have to forcefully check for updates. The phone will claim it is up to date despite me getting locked out of most of the phone due to company policies.
An engineer is expensive. Let's say it would take 12-16 hours of time in the best case for an engineer to write a deployment script for your scenario, debug it, test it, peer review it, and any additional hoops specific to the automotive industry. You are likely roping in other engineers (at least 2) plus a PM plus dedicated testers and a test vehicle. Let's make the math really easy and say the whole process takes 40 hours of someone's time at a reasonable rate of $150. That is $6k total.
While the development process would likely be a one-time cost, there would still be a manual process to specify update, approve the procedure, and any other hoops specific to the automotive industry (liability and safety if something goes awry). I suspect this would still be at least $1,400 worth of time and resources.
As a second owner, you did not contribute directly to Lucid's revenue. Your case is the most likely case of this occurring (exchange time between owners). There is no margin for them on your secondhand purchase, and servicing vehicles is a well known revenue stream for all manufacturers (some more than others). The expense could be much worse for a luxury vehicle for a repair item not caught during inspection pre-sale.