The author is factoring only market conditions and not taking into account the financial conditions of the investor. The expenses increases as the family grows, the kids grows and it sometimes becomes extremely difficult to pay that monthly installment, add to that home loan premium, vehicle loan premium, personal loan premium and so on.The investor gets stressed out to pay all the premiums on top of that sip. The brokers always recommend sip because they are assured monthly commissions, hence a regular income,with lumpsum investment these brokers gets only one time commission.
Humans normally get adjusted to little setbacks and can alter their lifestyle a bit for example if he lost a job, he can adjust with whatever savings he has or doing some menial jobs for survival and will be glad that he made lumpsum investment when he had money.Imagine his stress level if he has to pay SIP premium every month during those difficult months.
SIP is definitely a good option if life is predictable but unfortunately life is highly unpredictable. Hence our elders said save while you can.
SIP evens out market unpredictability and lumpsum evens out life unpredictability.So now you decide which is better option.
