OK. Let me clarify that.
There are two facts verified by Tipitaka references:
1. The Buddha stated that his Buddha Sasana would FLOURISH only in the first 500 years. That means there will be abundant Arahants at any time during that period.
2. However, his Buddha Sasana will not completely disappear until the Ariya lineage is maintained.
The above statements are also confirmed by the following:
– There were 1000 (or 500, I don’t remember the exact #) Arahants present at the Fourth Buddhist Council held about 500 years after the Prinibbana of the Buddha. That was the last Council conducted by Arahants.
– Soon after that the true and correct teachings started fading away in the MAINSTREAM. That was due to the rise and spread of Mahayana.
– However, there have been infrequent Arahants and people with various stages of magga phala within the past 2000 years. During this period, there could have been “small bursts of resurgence” due to the birth of Jati Sotapannas. We are in such a “burst of activity” right now, thanks to Waharaka Thero.
– I have discussed some of that in the recent post, “Yoniso Manasikāra and Paṭicca Samuppāda.”
The 5000 years number is a limit to how far such “small bursts of resurgence” can go into the future.
– I have read accounts in various places (I cannot remember where; it may not be the Tipitaka) that the absolute limit of the duration of the Buddha Gotama’s Buddha Sasana is 5000 years. Waharaka Thero has mentioned that too, without giving a reference.
– However, Wahraka Thero also mentioned that at the end, all the “dhathus” of the Buddha (remains of his body parts like teeth) will disappear. Furthermore, the number of bhikkhus will drastically reduce and they will gradually start living as householders. By that time, they will only wear a “yellow band” on their arm instead of wearing the yellow robes.
– That is happening even now in Japan to some extent, I have heard. But I am not certain.
– However, we are not even close to that worldwide.
Therefore, I think it is OK to leave that “5000-year” number as the duration of this Buddha Sasana (i.e., 2500 more years as the absolute limit). It just gives the idea that it is far from over.