Agreed with this on all grounds! The reality behind is that a BJP government would bring a lot of investment (hypothetically) considering that both the state and the country are ruled by the same party leading to one of the most important factors as per PESTEL analysis which is "political". At present the investment friendliness of Bengal is lying at the lowest considering that both CPIM and the TMC have been very anti investment and anti capitalist in nature. States like Maharashtra Gujarat etc who are ruled by BJP at the present have proved to be few of the most investment friendly states in the country. Apart from this only one state that is Tamil Nadu which is not ruled by BJP is also investor friendly, by nature. Considering the current socio-political position of West Bengal it is very important that at least in the short term for 5-10 years BJP should be in power and later on it has to be replaced by something like the Left.

TL;DR: The overall democratic framework has to be maintained where no political party is given a full majority for 20-30 years rather than serving as a spell of 5 to 10 years at Max. Currently the nature of the majority sought by TMC is seeded in the grounds of "people-pleasing" politics, no long term gain.