That same article points out that convention floor space has gone from 40 million sq ft to 70 million sq ft in the last 20 years, as cities have entered or expanded in an already crowded market. And your example of the success of Indianapolis is offset by the example of Houston from the same article, which defaulted on the debt used to build the stadiums and meeting space and has been sued by the bond insurer for insufficient reserves. Also, the bloom may be off the rose a bit in Indy, as the article points out, as revenues have slowed in the past year+.
So I still hold that convention centers are generally a bad public investment. And stadiums, too, at least they way most are funded.
kj