How would you feel if you attended a weekday Mass and the priest did not give a homily? Would it surprise you? Would you feel disappointed? Maybe even a bit cheated? Interestingly, that did not used to be the case many years ago. In fact it used to be fairly common for a weekday Mass not to have a homily. Our modern practice where there is a homily at every Mass is something of a novelty, and it can possibly lead to an errant understanding of the Mass.
What is the Mass for? We all know (though some know it better than others) that the Mass is not supposed to be for entertainment. It is not supposed to be amusing at all. It should be interesting, yes, but that is not the same as playful entertainment. Then, we can ask again, what is the Mass for? It is for the adoration and glorification of our Lord Jesus Christ. It is not an exaggeration to say that God is the audience and we are the performers in the Mass. When we get this point turned around, then everything will get messed up, and we cannot be sure that we are truly worshipping God (rather than some idol of our minds).
The modernist perspective on the Mass says that the people are the audience and the priest, altar boys and other ministers are the entertainers. Because of this, modernists are always seeking to catch the attention of the people and so they seek new and interesting ways to draw people in. Notice please, that if the people are the audience and the priest (and others) are the entertainers, we have to ask, "where is God in this paradigm?" If, however, the priest and all people are the "performers" and God is the audience, then it changes our entire perspective on both what the priest is supposed to be doing (especially which direction he is supposed to be facing) as well as the people's part in the Mass.
The homily, as it is understood in most protestant traditions, is the center of the worship experience. I recall when I was a Presbyterian pastor; I would spend about 15 hours a week preparing the sermon for Sunday services. Of course, the sermon was almost an hour long every week. But then, that makes sense with their theology. If the focus is teaching from the pastor, then that is where the effort is going to be put. These days, I do not spend as much time in homily preparation (usually closer to about 4 hours), and my homilies are closer to about 10 minutes. It is not a compromise, it is a theological issue.
What is the center of the Mass? No one reading this should be surprised if I say it is the Eucharist. Yet, what has happened lately is that modernism has infected our thinking. Churches are designed to focus on the priest, and liturgy rules are broken in order to focus on the priest. The end result is, the purpose of the Mass has been moved to focus on the priest (and not on Christ our Lord). Hearing the priest speak his own words has become one of the central points of the Mass.
Furthermore, when the priest is facing the people during both the homily and the consecration, it is hard to notice that there is a significant difference in what is going on. The priest is not speaking to God in the homily, he is speaking to the people (so, of course, he faces the people). Yet, if he also faces the people during the consecration is it hard not to think that he is speaking to them. If, however, the priest is doing the consecration while facing God, the people realize that the words said at that time are not directed primarily toward them, but toward God. The Mass is all about Christ giving Himself to us, and it is not about the priest showing himself to us. This backwards focus has caused many priests to think (and thus many of the laity to think) that much of the Mass is for the priest to say "look at me!"
Therefore, back to my original point. What about a Mass where no homily is given? Is it a rip-off? No. It is supposed to be for the purpose of keeping our attention on what really matters: the sacrifice of Christ brought forward in time to that moment, right there on that very same altar. It is possible that some priests will "skip" the homily because they are lazy, tired, or just did not want to prepare one, but that is not the only reason a weekday Mass would not have a homily (Sundays and solemnities are required to have a homily). It could also be because the priest wants the words of the Scripture readings to speak for themselves, and for the real focus to be obvious; Christ sacrificed for us and given to us, in reality, right there in our midst.