Sometimes I don't understand what the hey anyone is arguing about! Chamber music is not akin to the "fast food" of classical music! That would be like arguing that all wine is like ripple compared to whiskey! Chamber music by definition is music that was written for performance in smaller rooms as opposed to orchestral music composed for large halls or churches. You should also be aware that until the 18th century, chamber music was composed for serious music lovers (secular) as opposed to the grander forms which were written either for religious purposes to be heard in the larger spaces of Churches, or for princely court functions (Purcell's Funeral music for Queen Mary, Handel's Water Music or Music for Royal Fireworks comes to mind or any of the music of Rameau and Couperin composed for the Court entertainments of Louis XIV). Thus, much of the music written by J.S. Bach, including the Brandenburg Concertos (composed for and dedicated to the uncle of Frederick the Great, the Margrave of Brandenburg) is "chamber music"-- music composed to be performed in the more intimate setting of a palace room! Much of Mozart's work is also going to be classified as "chamber music" as well, including his symphonies which were composed for the 18th century orchestra which was much smaller than the modern symphony orchestra and performed in palace rooms. You should also be aware that until Beethoven composed the Symphony No. 3 (Eroica), orchestras rarely played really "loud" sforzando, hence Haydn's "Surprise" symphony's surprise is a sudden, very loud (for the time) musical note. It was considered very radical for the time and even shocking. In this day of expanded symphony orchestras and over amplified music, we lose sight of the fact that the ability to generate a truly loud sound from an instrument or orchestra was a technological breakthrough in the 18th century and early 19th century as well as a shift in musical esthetics.
Now, if you want to stigmatize music composed for quartets, quintets, septets of instruments and solo instrumental music than please consider this: Beethoven's most sophisticated and advanced music includes his late string quartets, his late piano sonatas (especially the Hammerklavier) as well as the Symphony No. 9. To equate his Grosse Fuge with Macdonald's is pure stupidity born of ignorance.
Now, a quick look at WCRB's
http://natrix.wcrb.com/cgi-bin/univ/univ.pl?page=playlist.html&station=wcrb shows that includes Mozart divertimentos and serenades, Haydn symphonies, Gluck, Saint-Saëns Danse Macabre (very halloween), CPE Bach Symphony, and demonstrates a nice balance between symphonic and chamber works! Before you start complaining, perhaps your problem is not the preponderance of Chamber music but a preponderance of classical period and late baroque music (symphonies in the "Gallant" style of CPE Bach for instance), or what is termed "light classical." If you hunger for Mahler, Wagner and Bruckner, then get some of their recordings. Those works, because of their length are rarely aired except at night, and frequently only in excerpts (for instance the Adagio from Mahler's 5th symphony seems to come up quite a bit). Using the search button here you will find very long and active threads dealing with these composers. Otherwise, try searching for other fm stations more to your taste.
Because you haven't heard chamber music that appeals to you, I would suggest that you start listening to more chamber music, especially the string quartets of Shostakovich (try Emerson Quartet), Beethoven's late string quartets (Takasc quartet has an excellent set as does the Emerson Quartet), String Quintet in C by Schubert (Alban Berg Quartet with Rostropovich), Mozart's Divertimento K563 (YoYo Ma, Kremer, Kashkashian have a budget friendly recording) -- a trio that is incredibly dense and complex, for starters. After you've listened to something like that, then come back and support your thesis that Chamber Music is just "fast food" classical. Btw, let's not forget the piano music by Chopin which is as complex, chromatic and brilliant as any symphony or for that matter Bach's Goldberg Variations. I'd rather have fast food by Bach than a lot of full 9 course dinners by other composers.