How long will the Action 4 be around?

I don’t want to deal with H.265 on the Action 5, so I’m thinking about grabbing a second Action 4.

Will they still be available until the Action 6 drops?

Maybe, maybe not. Is the Action 3 still available right now?

Once the Action 6 drops, there will be plenty of used Action 4s for sale.

eBay and other secondhand sites will always be an option once DJI stops selling it. Realistically, the Action 4 will be available for a long time.