Perhaps they are hoping for other platforms to take over the discussions in a more decentralized manner, spread over various channels. That being said I would have thought they'd rather transform their forums into a more advanced, better structured one to create space for improved discussions.
In general, Alt-specific forums are echo-chambers that do little to advance the Alt or platform...
And BitcoinTalk is now basically a complete waste of time... with marginal people spamming fantasy agendas, if not outright scams.
Ethereum is still 99% Devs, miners and speculators... most of whom were not using Ethereum Forums...
And frankly, the Forum fell between the cracks with (a) Devs on messaging platforms and (b) traders/potential end user types on reddit.
r/Ethereum... 11,800 readers...... 90 online
r/EthTrader... 3,900 readers...... 80 online
Let's compare reddit activity for other Top 10 Alts on a Sunday afternoon EST:
Bitcoin....... 174,000 readers.... 400 online
Litecoin........ 22,000 readers..... 15 online
Ripple............. 1328 readers....... 3 online
MAID................. 26 readers....... 3 online
Dash............... 1553 readers...... 5 online
DOGE........... 78,000 readers...... 33 online
Bitshares..........1024 readers....... 4 online
Monero............3222 readers...... 15 online
Factom........... 429.readers....... 7 online
So, in terms of actual mainstream reader activity on reddit...
One can argue that only BTC and ETH have broken out of the Crypto Ghetto (with ETH at roughly 30-40% of BTC activity).