Population density is likely the number one factor. We also have a very high number of people, vehicles and goods entering and leaving the country. Terrible air quality. Tens of thousands of infections when we came out of lockdown. Masses and masses of unrecorded cases throughout. Culturally, Brits seems to love milling together. There's no culture of personal space here. We're not very mindful of our bodies or environment, as a rule. Very much not minded to spot potential opportunities for beneficial cooperative behaviours. Incentivised by lack of social and financial security to ignore symptoms, not get tested, brush it all off. Anglo saxon bloody mindedness and culturally in denial over massive supressed negativity. "Old people die all the time", "No point trying, it'll kill more than it saves" "Just got to get on with it" etc. Extremely high incidences of heart disease and diabetes. And we have disastrously under resourced and willfully ignored problems in the NHS, social care, services in general. Also our PM was leaving every decision until the last possible moment.