I think investors would do well in general to study history and learn from it. History does not repeat but it certainly does rhyme.
The earnings have compounded beautifully in the last 12/13 years. But so has the pe ratio. However I can see 2 derating events right after major rerating events. Could this time really be different? Every investor must make their own judgement call by studying fundamentals,.tailwinds, capex plans, future growth triggers like pending US entry and also the reasons for the historic deratings and analysing.
Disclosure: I used to be invested because company is absolutely amazing business and industry definitely has good tailwinds but recently sold out due to valuations and the opportunity cost it implies in case of derating. Also, I really could not have deployed incremental capital that I get from my salary at these valuations so had decided to sell. However this is not a buy or sell recommendation, everyone must do their own analysis.