of course this can happen and it's not impossible, but of course it will be very difficult and requires high analytical skills, or just luck choosing the right coin to invest in, especially when the crypto market starts to recover, I'm sure many coins will start to rise
Anything could happen but how many times do you think OP could go wrong before achieving this. It is possible but again, it will be extremely hard to turn $100 to $7000 especially now that altcoins are not moving that much, the alternative is holding into altcoins and luckily you may get this kind of return but how many altcoins are you going to buy to know that this is exactly the one that will give you that kind of return. In every 100 altcoins, you will only get 1 or 2 altcoins that will give you such kind of return, the risk is high and I wouldn't advice.