Let's say the Norman conquest of England never happens. Anglo-Saxon England was relatively isolated from mainland Europe. How long would it have remained so? I doubt Ireland would have been conquered as the Anglo-Saxons were never interested in it.
I think in terms of Anglo-Saxon conquest, the saxons were very weak, they kept being conquered by foreign powers and having their country partitioned between disputed heirs, that isn't a situation that really lends itself to foreign conquest. Strong Kings such as Athelstan did enjoy influence at least in wales and scotland but that was lost when weaker kings took over.
Likewise the very feudal localised army structure of the saxons meant foreign conquest was tricky, because it was based around raising local levies to protect your area.
So for various reasons, there was never really a point wherein the Saxons were capable of invading Ireland. So Saxon disinterest needs to be seen through that lens.
I don't think that is always going to the situation, though. Eventually you are going to see the state centralise, a more professional army emerge, etc. To some extent that is already happening in the early 1000s with saxon mercenaries in France and Harold's adventures in Wales.
Ultimately England is still the largest, richest and most populous area of the British Isles. I wouldn't rule out a push into Ireland.
