I'm on Cryptopia doing research for new coins and I'm consistently amazed by the stability and vibrancy of the activity of coins with low to no developer activity.
Nothing from developers on BitcoinTalk.org's announcement page, no mining pools, broken explorer, twitter pages that haven't been updated since 2015, and yet the coin still has a market valuation, as presented by CoinMarketCap, into the millions and coins that are trading daily!
I'm tempted to believe that buyers of these coins are hoping that developers come back after a long hiatus and decide to devote 100% of their time to sending the coin to the moon. If you look back at the history of some coins you see them with a market cap of a few thousand dollars USD and then they do, indeed, burgeon into a multiple of that but these examples are extreme. I suppose that people believe that if they buy 100 no dev coins that 1 of them will skyrocket and justify the cost of the other 100. Given the activity in Dec/Jan 2018 that many altcoins saw this may not be as ludicrous a proposition as it may seem at first blush.
The extreme of this is I see on YoBit that some altcoins are selling even though the altcoin's wallet doesn't even work.
Lemon's coin is an example of a coin that doesn't have it together but take a look at the tightness of the bid/ask spread. There is a real market for this coin despite all of its shortcomings. And activity does take place.
With the relative ease it takes to start an ICO these days, it's improbable that a reserve-merger of sorts will happen to a coin such as this. Sure, for $10k many times a company could take a very large position in a coin and then develop a new website, wallet, pool, and get things running again but these funds could just as easily be placed into promotion for a fresh coin. Also, there is the possibility that a previous owner could dump their coins when the price starts to gain some momentum, derailing the new developer's efforts to be rewarded for their efforts. Plus they need the complete cooperation with the previous developers. Too many headaches are involved and the probability of this working out are slim.
There is also a possibility of a pump-and-dump group picking-up a particular dead coin and pumping up the shares. If one has Blockfolio and sets-up a alarm when their altcoin hits a certain price then maybe there could be another opportunity to sell while the pumpers are pumping and make-out with a handsome profit there as well.
I would be interested to learn if anyone invests into seemingly dead coins and their reasons for doing so. Please comment in the section below!