If in future difficulties of every crypto currency start rising then it's means new and more heavy hardware will be needed??
That is more likely the case But with increasing Difficulty there will be a increase in price as well. And also it is gonna take months before it all happens. But it will only happen if the Scrypt ASICS come out. That I highly doubt even exist. Also we already have 70-80% miners that switched from BTC after ASICS came so until there are no ASICS for Scrypt we are good to go.
1st gen scrypt asics are already out. Reputable people have received units, put up reviews, group buys have concluded. It is legit unlike the early days of bitcoin asics. Check the mining hardware section and look for dualminer, asiabtc, lightning asic etc. Prices are too high though. You'll really feel the pinch when 2nd and 3rd gen chips get out.
Mind you GPU mining won't die. People like you will just switch to memorycoin and the like i.e. non-scrypt, non-sha256 alt coins.
Actually if scrypt asic miners come out. Coins that we have mined now will be worth a lot more. And I think bigger and cheaper scrypt asic miners will launch at the end of 2014. i am not totally sure though. litecoin was launched in 2011, its enough time to make a cost effective machine within this time.