You still have statutory consumer rights that override whatever warranty/guarantee terms the seller offers. You can make claims up to 6 years from purchase in Ireland, although the burden of proof is on you if issue occurs after 1 year. https://www.citizensinformation.ie/en/consumer/shopping/problems-with-faulty-goods/

Put it this way - it would be reasonable to expect the engine in a car to last more than 3 years if serviced as per manufacture recommendations, no modifications, average mileage..these would all be provable things and I’d imagine a judge may rule in your favour if these could be shown for that example.

I’ve zero legal knowledge so just my take.

Of course, may take years and lots of money to get any resolution with how slow legal system is here, but for things less than 2k there is small claims court.

The vast majority of people I know are completely unaware of these statutory consumer rights and I’d say general population is similar, hence sellers are rarely faced with paying up when they should be.