Whatever they say, all others lose suction because their filters clog.
Other vacuums have inefficient cyclones. They can’t generate centrifugal forces high enough to separate the smaller particles of dust and dirt.
Instead, they rely on filters to capture these particles. This dust builds up, clogs the pores and blocks the airflow – causing the vacuum to lose suction.
With some machines, this can happen before a vacuum’s bin is full. It can even happen when filters are maintained according to the manufacturer’s instructions.