With the exception of the early years, mining has always been like that. In fact, even in the early years it was like that as well as bitcoin was only worth a few cents. The people who made money just happened to be in the right place at the right time (they had a lot of BTC early when it shot up), because even when bitcoin started to creep up in value, so did the miners.
But for the past few years, mining is always chasing the tail end of the race. Big companies develop new hardware, mine with them a few months, then once they made profit, sell it off to consumers as the latest and greatest. Antminer S8's are probably pumping away right now in private, and in a month or two will be announced as new and sold off to the public once the S9's are working in private. Rinse, repeat, but in the end the small miner ends up getting the shaft as they barely eek out the cost of their investment. Sure, low electricity can help, but even there it is only minimal.
Larger gains could have been made by simply buying BTC last August at or slightly under $200. A $4,000 investment (@ $200/BTC) would have netted 20 BTC. Now 6 months later you would have doubled your money ($8,000). I don't think a $4,000 investment in the S7's back in
I think so. The mining business is very difficult for home miners now. Your new miner will only have usable life a 6 months or less.