Trading Bitcoin is not profitable unless you have extreme patience and large capital to invest. If you can wait you just have to buy the dips that occur yearly and profit from the highs that also occur yearly. More than the lows as you can tell by the price;). Alts have extremely high risk vs reward. Only a few get lucky and when they do are they even disciplined enough to convert it into BTC and hold it long term?
You will need also a patience and a good amount to invest when you want to trade on altcoin and there are some coins turns to deadcoin so there are risks involved when buying a coin you will need to research unlike buying bitcoin
If you are new to trade its better to go with bitcoin because the risk in altcoin is more but some coins will give good bump.Bitcoin trading always good profits and the price of bitcoin also increasing everyday so it means profit.Like you said the trading needs good investment to buy more bitcoins and the price will go up soon which also gives profit.Buying then selling then buying bitcoin if you trade like that the profit is not enough so buy bulk amount once and trade for good profits.