And yet I have not found a convenient online store that has even close to as much as Amazon and is competitively priced. If I want to buy a monitor what is there? All the domestic dealers are beyond awful, and I can use overclockers (a UK site) but the shipping is high and soon I may have to pay tariffs too. I go to German, Spanish sites too now and then but even if they have what I want it's generally overpriced and shipping is quite expensive. I also need to go to 6 different places if I want 6 different things, so I can't combine shipping. If the EU wants greater union it might be worth making it as cheap to ship something from Dublin to Tallinn as from Boston to San Diego.
Though tbf I have been moving towards using more ebay, or dealextreme when I can (and am ok with waiting 6 weeks).
They already paid big chunks of the bills for Ireland's roads, ports and airports. Asking them to subsidise everyone's postal costs too is a bit much.
If Amazon _did_ turn up, would it have an effect? Probably. Would it be game and/or life changing? Unlikely, since these capabilities are already available in here.
You are correct that we are not used to getting everything from the same vendor. But it is absolutely common for people to order stuff online. Our "high streets" are just as empty as those in the rest of the world.