It's sometimes the opposite, see below.
There are some things that I know about this, and some that I only believe with moderate confidence levels. I'll try to be clear about which.
Fact: OLEDs have a different profile than LCDs. A fully black OLED consumes tiny amounts of power as it's doing pretty much nothing. The more pixels light up, the more power it uses. With "normal" LCDs, it's the other way around - the backlight is always on, and the more pixels aren't white, the more power that uses. Of course with that advent of dimmable LED arrays, the picture get murkier, as all-black LCDs now need less power because the backlight itself is using little/no power- but when showing bright content, FALD LCDs may use more power than traditional backlit LCDs.
Believed but not known: Tandem OLEDs have various benefits, including much better longevity and less susceptibility to burn-in, but they do use more power than regular OLEDs. By how much I don't know, though my impression is that it's moderate. They may also have higher baseline consumption for an all-black state - I don't have any data on this.
TOLED and LCDs will still have very different power consumption that's content-dependent. But TOLEDs - at least the ones on the iPP - do appear to consume more than regular OLEDs.
As for the question of scaling- @Pressure, I understand about mother glass and how that's developed over time. I am still under the impression that large displays scale cost up more than linearly with area, but I do not know that for certain, nor do I have any idea what drives that cost, unless it may be the defect rate in mother glass. I can well imagine the same dynamic that plays out in silicon being applicable here (driving the cost of large chips more than linearly by area compared to small chips, due to single defects killing more total silicon when producing large chips, and leaving out the workaround of binning, which clearly doesn't help for displays).
I'd welcome further data and/or corrections.
