One of the things people are overlooking with discussion on ADA vs ETH or BTC & its potential is they are concentrated on the total number of coins vs the total "pieces" of value of these products.
So for a direct comparison while its easy to look at the numbers & it appears that there are ~1,500x more Cardano than BTC, the reality for those who dig a lil deeper is BTC has 8 decimal points of value while Cardano only has 6 decimal points of value. So that means there are only ~15x more ADA. Same with ETH. Looks like there are ~260x more Cardano to ETH, but there are really ~2.6x.
So you can debate the worthwhileness of Cardano as an investment vs these other coins & other coins not mentioned IF Cardano really can become the 3rd generation cryptocurrency that its being hyped as. But if BTC is a $100k to $1M+ per coin at some point I believe the long term upside on Cardano could be very nice & in the thousands let alone $100 per coin.
That said there is obviously so much speculation & a long ways to go in this space who knows what goes where or what'll come next, but personally Cardano is one I'm invested in & have hyped it to non-crypto guys who just want the potential next big thing they can throw some money in today & look back at in a year or 5. Cardano will have to perform, but regardless of how big it gets I believe its one of the safest, less volatile bets out there right now.
RE: Why Cardano $ADA most likely will never be worth $100