Quoted from thechakapakuni:

Indiana Jones 4th movie is kind of like Stern Indy. We just don’t talk about it

Quoted from LTG:

Not my place. Might be covered by an NDA.
When it goes public. People will go Holy Fuck !
LTG : )
Disclaimer : This my well be the first time I know something. Usually I'm the last to know.

Quoted from brainmegaphone:Best guess is they didn't want to announce anything until they were ready to sell it.
Choice is announce something and miss all delivery targets (this form of planning is utilized by many in pinball and the video game industry) versus announce when ready to take money and ship games. Given the choice between the two I respect the latter much more.
Reason for delay? There are so many possibilities to speculate on:
10. Licensor approval?
9. Supply issues?
8. Software development issues?
7. Industrial accidents related to the creation of an 80" LCD screen for the ULTRA LE version (for those that demand the DMD be bigger than the playfield!)
6. Factory labor issues?
5. Serious food poisoning in the employee cafeteria several weeks in a row?
4. Several bad playfields that they decided to re-do versus just sell in the games?
3. COVID anyone?
2. Corporate employees at CGC find these circular speculation threads hilarious and don't want the fun to end?
AND THE NUMBER ONE REASON FOR THE CGC DELAY IS:
1. LTG's passionate hunger strike demanding PTC finally convinced them of the error in their ways... only to have him switch to some other unknown title (EFL?) which is resulting in serious confusion amongst the development team. People are quitting as a result.