I think it also has to do with the fact they're illegally crossing. If an American or a Filipino got lost in Europe they'd still search for them. Hell, every year here in Croatia we have to rescue Czechs who climb up mountains in flip flops.
I guess the reason is that what they're doing is illegal, and you don't have enough resources to track and save every single migrant ship.
I mean, I don't remember hearing Frontex or national coast guards completely ignoring sinking ships, they often try to save them from what I know, they just don't have as many resources.

But I do think rescue capabilities could be improved. I don't know how hard it is, but I feel like with modern technology, setting up radar combined with satellite imagery shouldn't be that hard. Ships stick out of the water a lot, so tracking the ships that are out of place shouldn't be too hard.

Regarding immigration, once I believed we should take in all refugees, but now I've come to realise that it's more complicated. Untill we figure out how to properly assimilate them into society, it will only lead to problems and disappointment on both sides. If immigrants huddle up into segregated communities they won't assimilate, they'll be poor, and that's the source of all conflict. I don't believe they're any different from us, nor that their cultures are completely incompatible, but if they become segregated they will be ostracized from society, they'll be poor and resent society for shunning them. They came to this land from so far away, hearing promises of how great it is, and then they live worse than they did back home. That leads to crime, more resentment and racism, leading to them having an even harder time. It's a brutal cycle.