They'll never do 120 minutes sets, the only way they can even do 100 minutes sets now is with all those interludes. More harder songs and longer sets are simply not possible for them.
LP will never be one of those bands that plays 2 hours + sets, that's a fact you should accept and that will never change. Many many bands don't play 2 hours sets either. LP has enough songs for that since 2003.
I personally think 100 minutes is more than enough. For all those years I've been seeing LP live there are always people complaining that not even 90 minutes is enough and some feel to be ripped off by such a short show lol.