DSCC posted an interesting article, comparing the production costs of OLED vs mini-LED panels for IT. DSCC estimates that for tablets and notebooks, a tandem structure will be used, and the panels will be based on rigid substrates.
In the chart above you see a production cost comparison, between 2021 and 2025, for 12.9" panels. DSCC looks at two OLED production options: a tandem OLED panel with an LTPO backplane produced in a 6-Gen fab, and a similar panel that uses an Oxide-TFT backplane and produced in a larger 8.5-Gen fab. As you can see, OLED panels are more cost effective, and will remain so throughout the forecast period.
As DSCC says, this brings up the question - why did Apple adopt miniLEDs in its recent tablets and not OLEDs? So first of all, tandem OLEDs are not available yet for the tablet market, and a single-stack OLED does not offer the lifetime Apple needs. Second, Apple may prefer a mini-LED as it offers a wider selection of suppliers.
For larger panels, for example 16.2", miniLEDs are more cost effective to produce as this size is not optimized for production in a 6-Gen fab glass size. This will change with the introduction of 8.5-Gen OLED fabs. For even larger sizes, such as 27-inch panels (for monitors), mini-LEDs could remain more cost effective to produce, even with 8.5-Gen OLED fabs