No growth despite adding new websites

Usually increasing investment, adding new websites will increase the revenues , however due to corporate espionage, however many websites are added, the income will increase by $3-4 a month for nearly 400 websites or in some cases decreases . Adding more websites, means more expenses, however there is almost no growth or decrease in revenues, reducing profit, causing losses
So at the end of the year 2017, it is time to do a serious review of whether money should be spent online, especially domains as other sectors are far more lucrative
For example just growing plants, does not take much time , and the plants are a passive source of food, leaves, flowers
The time spent on wordpress blogs, selecting domains is a waste, as there are almost no ads sold for new domains
It is better to spend the same time, money and energy on doing something else