In general or if you are talking about boats from the same lot, I agree. For boats that have a long production run or are produced in different locations, some are better than others. For example, the 1988(?) Alter Cup TheMightyHobie18's were all near minimum weight, did not leak, the sails showed signs of being individually trimmed, and the batten lengths were different. In the case of the H16 and Catalina 22, there were definitely some bad years. In some cases the differences fade over time and in other cases the bad years just fall apart(in the early 80's several builders switched to a "better" foam core that started delaminating after a short time)

The new boats seem to be more reliable and consistent than the boats of old but commercial companies do not have to tell you if they change something.