There are many countries in the west where prostitution is legal and taxed like any other activity.

It seems the main complain is that it brings the prices down due to competition from eastern europe.

Wouldn't that put at least some pressure into pursuing other options (like mowing somebody's lawn)?

Wow i never thought of that! I love this reasoning (no sarcasm intended!). Based on supply/demand, the lack of social acceptance leads to low supply which in turn makes sure the price matches the moral cost. I honestly wished it was not (considered) degrading and just as acceptable as any hospitality service, although in my culture it is indeed immoral to take or provide sex services. Even so if it still is degrading indeed there should be a matching cost, but damn economics is a tricky one.