There must be shit tons of things that go into the situation being as it is. Diplomatic deals with Hindu-nationalist India. Lack of allocated resources to recruit officers to enforce against illegals. Local politicans, mosques and 'community figures' sponsoring people through. Costa Coffee wanting cheap staff. The nation's money-laundering shopfront network wanting staff they can pay nothing under the table. Chinese espionage. Benefits being generous. Refugees fleeing actual war. Political capital from the Guardian calling you racist every day for years.
No one is honest about almost any of the above. It's all run through simplistic nonsense arguments such as 'vibrant communities' or alternatively 'enough is enough'. Can the government do what you have done and say Somalians are a bunch of worthless wasters and no one with a Somalian origin will henceforth be allowed into the country? There are a thousand things preventing that from happening. Do it anyway? Fine, but then you'll get called an ethnic cleanser and lose all your political capital to be able to do anything else.
Same process applies for almost any issue you can name. Let's build three million houses - great idea - but not only are the classic Nimby boomers on your case, but developers are on your case, George Monbiot is on your case, dog walkers are, estate agents, grannies, gays, smokers, non-smokers, everyone objects for their own small reason and these add up. Despite this complex web of paralysing bullshit, 83% of people, which is most people, live at historical levels of prosperous comfort. That is why all your political capital is tied up in the Waitrose car park shaking their heads about things, and that is also why nobody is radical and takes risks - because for the majority, life has been getting better for a very long time now, regardless of whether they feel it has or not, and no democratic government wants to be the government that gambled away that state of affairs. If you feel that democracy has run its course and dictatorship is now required, then that could be a legitimate argument, but I don't see a single person making it.
The only two properly radical British PMs in the last hundred years have been Thatcher and Attlee (arguably Blair, but not really) and they both inherited a pile of rubble. No rubble is forthcoming now unless there's some kind of external trauma (war or major economic collapse) on the horizon.
And that's not to mention the financial markets, who accounted for the Truss weirdos trying something different and would also have accounted for Corbyn had he ever got in.