This is not how transaction fees work, it is not in percentage or even fixed as you put it out, the transaction fee is based on how congested the network is and the network is not frequently high although we do sometimes experience high fees during congestion period but it is not always. What you should rather do now of you feel the fees are extremely low now is to consolidate your little inputs into one so that when you want to move out later it won’t have high fees.
You are correct. Maybe I should have used the following example:
Fee in BTC: 250 bytes×20 satoshis/byte=5000 satoshis=0.00005 BTC.
Fee in USD (assuming 1 BTC = $30,000): 0.00005 BTC×30,000 USD/BTC=1.5 USD.
vs.
Fee in BTC: 250 bytes×40 satoshis/byte=10000 satoshis=0.0001 BTC.
Fee in USD (assuming 1 BTC = $200,000): 0.0001 BTC×200,000 USD/BTC=20 USD.
There is absolutely no perfect timing for collapse of exchanges or anything else it can can be hacked which is something that doesn’t have a season to happen, you can also have your account suspended too so there is no need to trust any exchange no matter how huge it is. You can though split your funds in different exchanges if you really want to move them as such you don’t have everything on one exchange
The hacking part is a valid point, but what is the probability of this happening to even a small percentage of accounts at the top CEXes? I am talking about Coinbase, Kraken, Gemini, etc.
Another great point you brought is the account suspension. But then again, can't that happen if I transfer coins now vs. 6 months down the road?
And as far as splitting funds... sure if I had $5 mil, I would have done that, but the primary reason I am going for a single CEX is that they have the lowest exchange fees for almost all the coins (except one). I don't mind the extra book keeping and tax arrangements once they are sold; the primary goal is to reduce the fees by selecting the lowest fee.