Yes I purchased swift MT recently with knowledge of RS413 going out of production soon. As far as 3s support is concerned, don't worry it'll continue. Mehran (Carburetor version) production halted in 2012 however all parts are available from 3s as well as service open for it. Similarly you'll see old Alto and Liana still being services at 3s and parts are also available although for some parts you have to pay in advance and then after a week they call you to either pick up the parts or get them installed at 3s.
regards.
moreover newer gen swift which is due to come is built with lightweight, high-rigidity body (same in celerio and new alto where any part if hit/dented need to be replaced rather than repaired - ask about it from any good denter then he'll explain to you) have body weight 905 kg whereas current gen has 1050 kg. Also, it'll have lower HP (84bhp@6000rpm) as it'll be equipped with K12M 1197cc engine; moreover it'll be AGS not pure automatic transmission as in current RS413. Upside of newer swift will be air bags and other good features (may include hill assist, lane control, cruise control, vehicle stability control depending on PSMCL that what version and in what price tag the company introduce the newer swift).
check the attached Maruti suzuki swift K12m brochure to get an idea what PSMCL is going to offer in Pak in new swift
regardsNew_Swift_product_broucher.pdf (1.6 MB)