perhapss
Headphoneus Supremus
I have experienced this. I attended a concert that included the Rodrigo Fantasía para un gentilhombre in the Green Room of the Veterans Memorial Building in San Francisco. The room is about 30 ft x 60 ft. and it was small chamber orchestra and small audience. I sat in front, less than 10 ft from the guitarist. These were the best possible conditions you could ever hope for in a concerto performance with unamplified guitar. Yet whenever the orchestra came in even softly, the guitar was drowned out. Even under such ideal conditions the guitar needed amplification.
I truly believe that the classical guitar (which I love) functions best in solo settings or in combination with other guitars. There are some exceptions (like the Henze piece I posted with mandolin and harp but then again I've never heard that piece live). Just IMO. Amplified classical guitar can be interesting to me if the amplification is an intentional part of the composition. For me, part of the charm of composition for acoustic instruments is the way composers use their skill to control the dynamics/balance of the ensemble. Just IMO though...