Looks like it irks some people that Wizzair use Liverpool, indeed expanding at Liverpool an obscure airport that Czech Airlines also use.
The UK-Poland market represents around 6 million pax per annum. MAN is woefully under-represented in this market, hence calls for services by Wizzair and others from there in particular. I have not noted any calls on here for Wizzair to
leave Liverpool; there is a defined market for both airports. Please note that my posting did not label LPL as an obscure airport. Perhaps you think it is? Either way, its catchment area for Eastern Europe overlaps that of MAN but does not duplicate the majority of it. By the way, the same also applies to DSA and BHX ... you appear to believe this is some kind of LPL v MAN issue?
Liverpool is cheaper and half an hour down the road.
Half an hour down the road from where? This depends on one's individual location and preferred mode of transport. Early morning LPL departures and late evening LPL arrivals mean a costly hotel nightstop for me and I'm located in the MAN area. All LPL flights imply much higher ground transport costs from my location also. The customer proposition presented by using the two airports is very different (and of course this applies both ways). Densely-used routes such as those to Poland require exposure from both airports, but certainly more than the current ten weekly departures offered from MAN.
As for LPL being 'cheaper', can you tell us exactly how much cheaper than MAN it actually is (since you seem to know?). Do you suppose Ryanair are paying big bucks at MAN? I suspect that the difference paid by ULCC's at the two airports is very small indeed, and remember that airport charges at one end of a route represent a tiny proportion of the overall cost of providing a scheduled service.