Buddha -> Vedāna -> Nibbāna.
[ Seven Suns Sermon, “Buddha seeing this world and all worlds”, Buddha’s omniscience, Digha Nikaya 26 & Madhyama Āgama 66, Simsapa Leaves Sermon]
Modern science says our sun will become a Red Giant and may consume our planet during this process. Buddha saw this 2500 years ago as told in his seven suns sermon. Buddha being able to see this far would easily have been able to see another Buddha arising in this worlds future. The reason for there being only 2 references among EBT’s to Metteyya(future Buddha) may be the Simsapa Leaves Sermon. My interpretation of Digha Nikaya 26 & Madhyama Āgama 66 is this: Buddha reveals to a disciple he will attain to Buddhahood in our worlds future, the DN26 is a metaphor to Buddha being the Wheel Turning Monarch and the next Wheel Turning Monarch being Maitreya, DN26 also serves as a metaphor to the monks suggesting what happens if they follow their own ideas and neglect Buddha’s dhamma. The whole 80,000 year lifespan is only used for this metaphorical purpose and is not literal. DN26 also mentions that at this time of Metteyya, Jambudipa(earth) will be very full of people and cities, which is where humanity seems to be going.
I would like feedback from you guys about this.