The sales haven't ever matched OOO's again, but OOO had ridiculously good sales compared to almost any other series. Decade had very good sales per quarter, although it would still be beat by Ryuki, Faiz and some other earlier Heisei shows due to having a short run. W went on to beat Decade's sales and stand above any previous Heisei series. Comparing to Sentai, W by itself beats every Sentai series aside from Ohranger, IIRC.
OOO actually was another leap from W, resulting in a very large number. In a single year, it sold more merchandising than Sentai usually does in two. Fourze's numbers were very close to OOO's too. Wizard was a drop, although still above W, Gaim recovered sales, but didn't quite get to OOO's and Fourze's numbers since there was a drop in the 2nd quarter. Drive has seen a really big drop in merchandising sales compared to all those series though. The 1st quarter was good, although bellow any of the post-Decade shows aside from W, but the 2nd and 3rd quarter have had very low numbers, going to bellow Decade levels. The 1st quarter numbers still should carry Drive to around W's level though.