According to a recent survey (a thread I created), only about half of Catholics understand the true teaching on the Eucharist anyway. Couple that with the fact that in other surveys, Catholics answer incorrectly on beliefs concerning homosexuality, abortion, and contraception while conservative Protestants are the ones who display a proper Christian understanding.
Furthermore, many times the Mass in its current form - everything from what people wear, to how they act, how they receive the Eucharist, the songs - does not really elevate one to believe they were surrounded by the presence of Christ.
So when Protestants don’t think they’re missing anything, the more proper interpretation is that Catholics as a whole do not demonstrate the centrality of the Eucharist as anything that actually guides them to lead Christian lives and obey the Church’s teachings. In other words, what kind of example is a Catholic who receives the Eucharist but supports abortion, homosexual relations, and contraception? The faithful Protestant can claim (and per their conscience, rightly so, in my opinion) that reception of the Eucharist, based on the attitudes of Catholics, does not impart any type of actual grace which leads them toward the path of Christ. So why would they bother? It’s because overall, we haven’t really practiced what we preach and live the way we claim to believe.
We have failed people like @wannano above, because we didn’t act like we were in the presence of anything special.