For a country to host such an important tournament, it needs to have a semi-ok stadium. A country which has a semi-ok stadium usually has got a smi-ok football as well. Do you think that country don't have its own football teams and schedules to let a whole stadium be occupied by irrelevant games of 40 teams?!!! I mean even if they wait until that country's football league season is over, playing all the games in one stadium is an impossibility as some of the games have to be played at the same time so their results wont influence each other.
Also there are more costs for this than you think....stadium wear cost is one of them. Add to that the problem of choosing a proper common host country which is accepted by all the teams (even if you choose several host countries, that can be a problem). I think this is just not a good and logical solution.
It clearly shows we have so much experience and knowledge in the field of organizing big football tournaments, ay? lol