there really isn't any kind of limit to how much you can profit from investing in altcoins. it can be from losing 100% of your investment and going down to 0 up to millions of dollars!
it depends on a bunch of things. starting with your experience in trading and in knowing how altcoin market works conversely the pump and dumps. if you have no experience and want to randomly buy based on what others tell you and what they hype up then you will end up losing a lot of money.
then it also depends on how much you are willing to invest and take risks. obviously you can't become a millionaire investing $1 but you will be taking a much bigger risk investing a higher amount.
I support your claims mate. For my little experience I have acquired, following speculations and baseless predictions to make investment decisions could lead to loss of money. Individuals who pose as experts of cryptos most atimes predict based on intuition and they are likely to make wrong predictions.
Many others who predict Cryptos rise, do so for their own interest because of their affiliation with the team of the project/Altcoin.