Don't think so. We should not invest in any Altcoin. Investing must be done wisely. We must choose a trusted Altcoin. So that the money we invest does not disappear into dust.
But you're missing the point from the question. Investing in altcoins to generate x amounts is still possible right now. The money won't disappear as long as we was only putting it intot he legit coins but OP asked how big possibility for him to gain x return from his investment in altcoin. Investing in altcoins to gain specific return makes more sense rather than invest in the native coin which has been trading at the top.