~のは…ぐらいのものだ => only (emphasis) N1
Limit
というのは => because N2
... というのは => It means... N3
Explain
たものではない => Impossible N2
Evaluate
のでは => if N3
Condition (hypothetical condition)
... ないものは ...ない => is not entirely impossible N3
Ability
…のも無理 (は) ない => It's natural for... N3
Evaluate
というのは => this means; the meaning of … N2
Explain
と[言「い」]うのは => Means, is N3
Information, Report
とはいうものの => having said that; be that as it may N2
Things do not match the prediction
というものは...だ => something like; something called ~ N3
Explain
ものではない => shouldn’t do something; it’s impossible to ~ N2