The scale you refer to as limited is not because of ArcGIS Online limitations. The basemap you are working with (those that are available as Basemaps in ArcGIS Online) has been cached in certain scale levels (the largest scale is ca 1:1128). That is why you cannot zoom in any further.
However, you are not limited to ArcGIS Online basemaps. Feel free to add your own tiled map service (either cached locally in ArcMap and uploaded as a tiled package or cached at ArcGIS Online side by using Esri's computational resources).
When you will search for the layers to add, click the item in the Search for Layers panel and choose Use as basemap. This will replace the standard Esri's basemap with the basemap of your choice.
Please read more about adding basemaps into ArcGIS Online here in Esri Help page.