Idea of premium package is to separate expensive stuff from non-expensive stuff to allow more
price sensitive customers afford the vehicle in the first place.
Ideally, only expensive stuff should be removed if no premium package has been opted. Unfortunately,
often (and in case of Model 3 as well) some not expensive stuff is also removed.
- Premium heated seating and cabin materials throughout, including open pore wood décor and two rear USBs
Well, material can be costly, though non-leather materials are usually not (compared to cloth).
Real wood panels are expensive to manufacturer. Even one big one can add 100-200€ to manufacturing cost.
USB ports are not expensive. Making two different parts as wirings is even more expensive for manufacturer than offering
only one version that has those ports.
Seat heating is usually standard on most EV's. It's not reasonable to offer version without. Manufacturing price difference is marginal (100€ per seat, 300€ total).
- 12-way, power adjustable front seats, steering column and side mirrors, with custom driver profiles
Electrically adjustable seats (especially with more than 6 directions) are more expensive (500-1500€ extra per pair). Electrically adjustable steering column is slightly more expensive compared to manually adjustable (100-200€). Manually adjustable mirrors are lost in history.
It's reasonable to believe base seats will have 6 directions, manually adjustable.
- Premium audio system with more power, tweeters, surround speakers and subwoofer
Quality speakers and amplifier do cost money. Standard audio should have at least 6 speakers and no sub with average amp.
- Tinted glass roof with ultraviolet and infrared protection
Glass panel does cost more than sheet metal, but it's weird to remove that part due to huge rear window. That also costs money and can't be removed.
- Auto dimming, power folding, heated side mirrors
Dimming mirrors cost significantly more than regular ones. 200-400€ per 3 mirrors. Power folding mechanism costs very little (like 50€)
Side mirrors that are not heated is almost not acceptable on modern vehicles, that includes cheap ones.
They add almost no extra cost (5€ each). It's reasonable to believe dimming function will definitely be premium option.
Cost is marginal. Functionality is also marginal. Somewhere around 100€ per vehicle.
- Center console with covered storage and docking for two smartphones
Hardly premium feature. If not opted for that package, supposedly open storage compartments with USB ports will be used. Therefore fingerprint magnet surface will end with cupholders.
Summing that all up, $5000 is pretty close to the real value. Slightly too much (mostly due to "premium materials" not being premium enough).