Not sure who you are responding to but here are some figures...

Not sure who you are responding to but here are some figures that may be used for forecasting.

The total number of sims in Indonesia is around 435 million (if what the companies report is accurate). According to the latest companies' annual reports (Dec 2017), Telekomsel had 196.3 million customers, Indosat had 110.2 million, 3 (Tri) had 63.6 million, XL Axiata had 53.5 million, and Smartfren 11.5 million. These figures are sim cards not individuals. The Telcos call them 'customers', but clearly they don't have 435 million 'customers' in a country of 265.4 million people.

The number of unique mobile users (i.e. individuals not the number of sim cards they own) is 177.9 Million (Source: We are Social, Hootsuite, Jan 2018). It's actually a very good number for a country of 265.4 million and where many live in isolated or rural areas with basic telephony. Therefore, if we say that Indosat has 110.2 million sims sold, it doesn't mean they have 110.2 million physical subscribers.



You have to also consider other factors:
- The majority of mobile phones sold in Indonesia are dual-sim. The minority of people with single-sim phones just swap from one sim to another. Some people have 3 sims. That is very common in Asia.
- Between 98-99% of the sims are prepaid. Indosat figures is 99% prepaid (Source: Indosat 2017 Annual Report)
- Only 70.22 million users in Indonesia have smartphones (i.e. capable of downloading apps). That's about 40-43% of the total Indonesian users. (Source: Statistica 2018). Even if Indosat had 50% of those (unrealistic) that leaves them with 35 million smartphone users)
- Intrusive ads, targeting ads, and mobile ads are the main reason of user annoyance and abandonment of applications in Indonesia (Source: GfK Consumer Survey).

The attrition factor is high but it spreads randomly between Telcos. One day Telco A offers a deal, people jump on it, Telco A subscribers increase by 20% or more, but because they are mostly prepaid, if tomorrow Telco B offers another deal, they will leave Telco A for the other deal. That explains the unusually high number of sims considering the total population. Unused but active sims (after a year they become inactive) are still considered a 'customer'.

That is to say that it is hard in Indonesia to predict how many actual individuals will subscribe to a given service. It has been a headache for forecasters and business planners, and one can only rely on actual figures post deployment. I have tons of surveys and analytics, but the majority are post fact (happy to share if interested).

You are also correct about the ramp-up, usually it takes time and is measured post free-trials (if offered).