Fuel pumps are susceptible to seizing from sitting when fuel contains ethanol because ethanol causes the nylon impellers to swell. Also ethanol absorbs water so you have the corrosion factor as well. But that's why motorhomes are disproportionately affected by fuel pump failures.
Bruce - not sure if you are aware that fuel stations in Oregon can now sell non-ethanol premium. I always recommend it for customers whose cars sit a whe or don't get many miles. All of the astro, wilco, and PAC pride stations carry it as do some 76 stations.