It might also complicate the manufacture of the container.
A similar problem exists with aerosol cans holding liquids. Any unused product or propellant goes to the waste system. Thereafter one more problem environmentally.
Popular anecdotes for common products is that the packaging - containers often cost more to produce than the contents. Someone I know who had inside knowledge of CUB suggested that beer was an excellent example once all the added Gst, excise, marketing, distribution and various retail costs/profits were added. Although it’s uncommon to have a similar problem getting the last of the contents out compared to a pump pack.
Is the real problem with pump packs that they are pump packs?
Are there alternatives?
For hand wash we buy refills and reuse the pump pack, lotions mostly screw top jars, for detergents pop tops. The notion that the pump top on a container is a single use and one way to landfill outcome is worthy of an industry wide environmentally shonky, IMO. Of course consumers could opt not to buy them and feel the good.
I’ve nothing against pump tops if the pumper is reliable and long lasting, and the container permanent or easy to drain if interchangeable.