Yea, like people spend 600 euros for a 1-day choco nade to keep it around.
To sustain that thing for the 5 months, you'd need 150 days worth. Do the math and see if any sane person would spend that much euros.
Imma let you finish but people in SF have been known to stack years of costly items. For instance clan shirts are essentially 10x the price of 09 for 1 month and players have been known to stack them for years.
SP (the euro equivalent in SF) items have been known to be stacked for years, sometimes costing 200k SP a year.
Seeing as the AvA community is far larger than SF's I wouldn't be surprised to see such item stacking. However you do have a point.