A dinosaur with too technologically backward thinking or does he have a point?
http://www.zerohedge.com/news/2017-07-27/digital-currencies-are-nothing-unfounded-fad-howard-marks-calls-bitcoin-pyramid-sche
http://www.zerohedge.com/news/2017-07-27/digital-currencies-are-nothing-unfounded-fad-howard-marks-calls-bitcoin-pyramid-sche
'Pyramid scheme' here is a figure of speech. And he does have a valid point.
Until bitcoin becomes a currency used for transactions (for all intents and purposes it is not yet one) its value depends on the influx of new speculative money. Hence the reference to a pyramid scheme.
No to be taken literally.
Capitalism in general depends on new money, wether by expanding markets, or opening new markets. Industries that don't get new money, die.