Most businesses have tight overheads regardless of size.
In addition, Labour made sure to protect small businesses.
The NI rise for a small business (less than 50 employees) may have increased NI by £4,312/yr (49 employees, aged 21 and over in the UK working a 40-hour week for minimum wage is £26,437 for 2026/27, resulting in approximately £1,109/yr NI per employee of which £88/yr per employee is due to the increase.) Labour doubled the EA deduction from £5k to £10.5k, meaning for many small businesses the entire increase in NI from 13.8% to 15% was offset.
The drop in threshold to £5k/yr earning will have also generated additional NI costs but really that is correcting an injustice for workers in often zero hour contracts or very part time work where no NICs are credited for their future state pension even if they are working several of these jobs so they are working full time overall.
Your local pub is not likely to employ 50+ full time employees. It was likely to be abusing workers rights and preventing them from accruing NICs towards a state pension by using zero hour contracts to keep annual wages below £10k (now £5k). The change removes much of the incentive to use zero hour contracts.
A large business of 10k employees will have many highly paid employees, their bill is going to be around £18m/yr. The EA offset is still only £10.5k. Depending on the overall financials of the business this could be easy or difficult to absorb.