The Sonus Faber Stradivari is WAY more than $20k, and it is ported. The $200k Wilson Alexandria speakers are ported, as are Audionote speakers, Classica Audio, and a host of others. There are plenty of sealed box speakers under $100 a pair.
It is not hard to design and build speakers that are either ported or sealed, so cost is irrelevant.
It is not hard to design and build speakers that are either ported or sealed, so cost is irrelevant.