I have already addressed this in my topic here: What the price would be if there is no Bitcoin scaling in next 5 years?
https://bitcointalk.org/index.php?topic=1771426.0;all

Just to summarize: First of all I'm huge BTC fan, had account here since 2013 and always been bullish - I don't want to draw any doom scenarios.

But if BTC ends up with higher fees higher than in a range of what an SMS costs in retail I don't think it's going to thrive to say the least - in my opinion the fee shouldn't be higher at anytime than 0.1 USD - whatever it takes..