You make some great points.
My "thoughts" :

1. NO ONE has a crystal ball!
2. BTC may or may not go up or down

• 'new' money entering the market will head to BTC due to media attention / BTC recogntion
• 'bankers' do not and cannot control BTC - they may spend a LOT of media $$ to wipe out BTC (and then buy in themselves!!)

1. ALT coins typically have more 'asset value' eg steem vs BTC
   ie they represent 'something' other than just the coin itself.
2. All crypto only has 'value' due to demand.
   A drop in demand can mean a wipeout
3. Any 'coin' can be surpassed by a 'better' coin at any point,
   ie the market is volatile

Bottom line: Only 'gamble' the amount you can afford to loose. Not your rent or food money.
I saw DOT Com boom & bust (things can move very fast with computers!)