“Three years after Boston Lyric Opera staged a free production of Carmen that drew a stunning 140,000 people to the Common, the company has reluctantly shelved plans for a follow-up event, concluding that it couldn’t find enough local corporate support to underwrite the show. After wrestling with funding for months, the opera company announced yesterday that it has scrapped a free production of Aida set for September 2006. The abrupt cancellation is a sign that local arts groups are starting to feel the impact of recent corporate mergers and acquisitions, which have diminished the number of companies with home bases — and loyalty — in the region.”