I don't know what Rafa thinks, but from the comment on Aqualani, it seem like chicken and egg theory.

Aquilani recovered from injury just fit, don't have match fitness, so can't play him or can't start him, but if you don't start him or play him, how can he gain match fitness?

Same with youngster

Youngsters are inexperience, can make mistake and resulted losses,
If you don't let them have some chance to play, how can they gain experience and improve.

Or the reserves team/youngster are that bad? which I don't know. 

But if those youngster are that bad, no point keeping them as well.

I don't see Liverpool has new face of youngster which being promoted from reserves team, may be except Insua.

Sometimes I really admire and salute Wenger has sharp eye on talent and dare to give them a try. Some risk need to be taken to try it out sometimes.

I don't mean criticising Rafa, as every manager has their fair share of poor signing as well, but Rafa until now is not known for shrewd in dealing in transfer market (he has no control of transfer back Valencia time). He also new in transfer market.

Apart from Torres and Macherano, others so so only while Liverpool often don't get cheaply on its transfer target while most of the time lose money in transfer market. (buy 5 million and after a year or 2, no good, ship out with 1-2 million)