I agree with you, but given that they are widely (incorrectly) believed to be the cause, I would say this is a really strong reason for addressing it.The small boat people aren't the reason the NHS is knackered, the Royal Navy can't put a single nuclear attack submarine to sea for months at a time, or why young people can't afford a house and have to live in house shares into their 30s. They're a problem but if they all vanished tomorrow all those things would still be broken.
Once irregular boat crossings are down, people would be forced to confront the actual solutions and trade-offs involved, many of which would be unpopular but necessary.
(Sometimes I think politicians don't want to stop boat crossings because they provide a useful scapegoat, in a similar way to how I think Reform don't want actual power - either they fail to stop the boat crossings, or they succeed and fail to solve the problems they said they were causing...)