Why is it "Dáil Éireann" rather than "Dáil na hÉireann"?

Luann na Bráithre gurbh amhlaidh atá, ach ní thugann siad cúis:

"Fágtar an t-alt ar lár roimh Éireann i dteidil reachtúla áirithe; Dáil (Seanad, Raidió Teilifís, Iarnród, Tuaisceart)
Éireann, agus i seanleaganacha: oileán iathghlas Éireann ... feara Éireann ná a mná. Ní hionann an bhrí a bhaintear as an teideal polaitiúil Tuaisceart Éireann agus as an ngnáth abairt tuaisceart na hÉireann."

Perhaps it's got something to do with the uniqueness (in the eyes of their founders) of the institutions so described. For example, "Dáil na hÉireann" could be read as the Irish Dáil; one amongst many. Others could include Dáil na Breataine, Dáil na Fraince, Dáil na nOilean bhFilipeannach if you get my drift. Ditto for Iarnród na hÉireann, one railway system amongst others. So perhaps linguistically speaking describing these Irish institutions thus; Dáil Éireann or Iarnród Éireann somehow puts the emphasis on them to the exclusion of all others.

I notice that over the years University College Dublin has gone from being Coláiste na hOllscoile to An Coláiste Ollscoile. That seems to be a bit like changing it from The University College to The (pronounced thee) University College.

Phew! I better stop.

On a related matter has anybody noticed the trend of late on RTE radio, R na G excepted, in referring to Dáil Éireann as the 'parliament',the Gardaí as the 'police'and even the Taoiseach as the 'prime minister'. Maybe its just me. Is fuath liom é!