That was part of history till 1960s when Karachi was Capital of Pakistan but after that things have Changed especially when Capital of Pakistan was Shifted to Islamabad as in 1970s Karachi started getting Ignored by the country and its prospects started coming down. That was not MQM's Fault but it was Nationalizing all Karachi Industry and then Introducing Quota System that took everything away from Karachi and in 1980s Afghan Refugees brought Gun and Drug Culture to Karachi which Actually Brought Violence in Karachi and makes things even Worse and JI was the one which started using Weapons in Karachi Politics not MQM so putting every Blame on MQM is totally wrong what MQM did was inherit the decline that was going on since 20 years before MQM came to picture. Read some history before coming up with your side because what you claim are totally wrong.That's not true at all.
If you read some history, you will see that Karachi used to be an economic hub for the entire region in the 60s-80s. International flights of most airlines in the World used to come at Jinnah terminal. Europeans were a common sight in Karachi. But you knw what happened? MQM happened. The resulting violence, extortionist mafia, land grabbing etc that started because of MQM scared all foreigners away to Mumbai and Dubai.
MQM does not understand the importance of enterprise. If it did, they'd care a little more about law and order.
MQM is indeed losing lot of support in Karachi and this has been very much Recent Phenomenon rather then old one started since 20012 and it is due to MQM sitting with PPP in Govt. Those are REACTIONARY things even I also voted for PTI in last elections but watching PTI last two years have disappointed me and if you ever Visit Karachi you would acknowledge that these days it is same trend in Karachi PTI support is declining here and MQM is gaining some grounds back. Even during 2013 Elections I know Countless people who were only ready to Support PTI for NA seats while still supporting MQM for PA seats. MQM has gained lot of Grounds during Musharraf regime and that Vote Bank is still intact. The Loyalties with MQM is proved by 1993 Elections when State itself trying to stop MQM but MQM won by landslides on PA elections in Karachi(MQM Boycotted NA Elections in 1993).This is also not true.
My mothers family used to be the biggest staunch supporters of MQM I've seen. All used to vote for MQM. Especially my uncle he used to go to any length to praise and defend MQM in political discussions and it used to baffle me I thought he was brainwashed.
But when I visited them last year everything had changed. Pretty much everyone in the house either voted for PTI or JI.
Same case with many of my friends. They used to live and breath Muttahida but over the years seeing what they'd done to a Karachi where once you didn't even need to have mechanical lock in your home and a kundi would suffice and children could roam and play wherever they wanted, their perception changed too.
I have literally seen this happen so no there's no 'loyalty' anywhere.