I purchased the FSD upgrade from EAP for $2k a few days ago. I think the reality is that it's a gamble and people need to decide if they like their odds. I don't think there's a right or wrong answer that applies to everyone.
Personally, I'm taking a $2k gamble that HW3 will be delivered to people who've purchased FSD prior to HW3 being both released and required for FSD functionality. I'm taking an additional gamble that the upgrade will actually be available for MCU1 and/or AP2 vehicles. We have what appears to be a statement from Musk that says we get HW3 retrofit and I think Tesla will make a good-faith effort to deliver on his statement, but absolutely none of know for sure that a retrofit is possible for every AP2 and higher vehicle.
As part of my gamble, I'm making an assumption that FSD will either increase in price when true FSD features are available and/or that the HW3 upgrade will no longer be a free upgrade once it's officially available and required for FSD.
I think whatever HW3 upgrade we do get will be the bare minimum required to make it work and if it does require additional upgrades to MCU or other components that there's a good chance that Tesla will opt to refund the FSD costs instead of delivering a potentially very expensive or impossible upgrade.
Of course, like any gamble I may get nothing out of it, but I'm just not going to lose any sleep over $2k.