Who said that investing in NEM super node is deal of life ?
At end markets always are seeking balance but you must agree that 300x3m supernode at 30BTC is quite impressive amount.
For people who are not afraid put 30BTC at  any coin super node is quite good addition to overall investment.
For some people having supernode is more prestige than some sort of investment.
And what is quite good those nodes are free from hack because of delegated harvesting and such calm sleep you won't have in most of
"nodes" around. I won't tell anyone that getting 3m of xem is his deal of life because price can just go down and week later it can go up.
Gold is less risky but then you can get fake gold bars like once USA wanted cheat China.

PS: Maybe when i go on retainment i will be able to live from having supernode - you know that is my dream,
but noone knows a future.