I think we are on the same page regarding the reasons for eternal life. Maybe the pill will come in the ability to download our brains, our knowledge, our consciousness. Then we can easily end our life as well, if we manage out backups right (ie 100% control them and being able to delete them).

If the 'Eternal Life' pill would have the characteristic that I could end my life whenever I wanted, I would for sure take it. However, if life would indeed be eternal without any chance to terminate it (assuming any new technological or whatever new development will also not make it possible to end the chosen eternal life); I still find eg 100 Gazillion years living quite a long time and this may be a bit too long; living may get boring, I'm afraid, and when having a boring life even 100 years is long.