On asic's if there is money they will build it scrypt proved it. Right now SFards is mining LTC internally with the newest gen LTC machine.... no selling to regular customers except a very few. But it was profitable enough they dumped some money to develop a next gen. If any other algo ever had a coin that had huge profit's they would look into it... and chances are eventually make a asic assuming it is worth the R/D and dev.
On your fiat crashing... which country are you talking about? Fiat is not really in competition with BTC. So I would not tie them directly. Fiat will always be a part of society for foreseeable future. There are just some you would never be able to convince to use BTC.
On mining we need to know much more. Jumping in with 20 miners is not easy... you need electricity that is cheap or decent, and 20 is a LOT of power. Have you looked if you have a place that can even handle that much? There is just so much to this part if you plan on mining with 20 miners somewhere you own.
As far as fiat currency goes I am convinced that the United States will see a crash within the year and bitcoin is an excellent form of currency.
Assuming that 20 Antminer S7's can produce 100 TH/s by profitability calculator which would result in a decent amount of profit but I'm more interested in a currency that actually matters. If anyone could point out my foolishness or anything I'm particularly missing I would be interested. The only thing that really holds me back from doing anything with this is the difficulty increase which is detailed in the graph in this link:
https://99bitcoins.com/bitcoin-mining-profitable-beginners-explanation/
Regards,
If you are absolutely convinced that USD will crash, then your path is clear. Just take the $25K you would invest in Bitmain hardware and buy BTC as soon as you can, and skip the "Bitmain middle man".