I saw something on a friend of mine iPhone I was amazed, this guy has 3 pieces of bitcoin but he didn't look it when you look at him with mere eyes, I ask him how he has come this far, he told long ego he was seriously investing on all kinds of coins with little amount of bitcoin but then most of those coins help him to realized enough amount to buy more bitcoin because that was his primary target. He normally buys those zero value coins when they appreciates it will be enough money, and that's how he convert and swag all to bitcoin and today, he has 3 piece. Is good to be diversified in your investment, somedays something good will come out of one you don't expect.
Know that every investment does not guarantee success and profitability, that’s why if you have the sufficient funds for capital, learn to diversify your investments so that if one investment fails, other investments will still have chances to succeed. However, on part of OP’s friend, he uses altcoins just to achieve his goal for bitcoin. Maybe that was only applicable when altcoins are still profitable but seeing how the altcoins these days gradually lose their value, I don’t think investing in altcoins aside from bitcoin will still be a wise move.
I agree that it is not going to be that easy, I know that it will take sometime but eventually we are going to be able to do it. Diversification is a hard thing to do because it is not easy to find these things quickly, most people end up investing into either nothing different and just top names, or they end up investing into silly stuff that shouldn't be invested.
I always aim at top 10 coins, maybe a bit higher after that but that's the point, not the stable ones though because stable coins are stable as the name suggests so there is no need to invest into them. I personally like to do what I do and there is nothing wrong with that, however I would suggest everyone to find their own thing they like to do and diversify based on that.