Mining is now an industry. You can't just mine with a pair of your spare GPU let alone your i3 processor (Excluding the useless coins, of course).
So, it would be better just to buy and trade. Even for new coins, it could be beneficial if you strike a deal with the miner before the coins get listed in an exchange.
You right that time of mining with single GPU\CPU is over. But mining with GPU farms or several ASICs is accessable for practically everybody. If you can solve noise and heat issues of mining machine you do not need to be a corporation you can be involved in mining