^^because the clubs dont have the money.
Its improved alot over the last few years. Some teams have done quite well in the Champions League and UEFA Cup qualifiers. Derry City beat IFK Goteborg a couple of years ago and Drogheda United ran Dinamo Kiev very close in this season's champions league qualifiers.
Unfortunately alot of clubs are struggling financially and cant pay players as much to play. All the good players move to English teams at an early age.
Also, hurling and gaelic football are more popular in terms of support and the population of the Republic of Ireland is only about 4 million