Actually, to make tofu tasty you need considerably more than just a few spices.
That is entirely subjective. You can make tofu extremely tasty with a short marinade in soy sauce. Fish sauce. Wine. Coconut milk. A dip in water or egg, bread coat, short fry, and you have the makings of a great tofu parm. Shred and mix into tomato sauce for a faux meat sauce. Cold smoke, dice, mix with rice, cheese, and you have the start of an excellent burrito/taco. Silken tofu can be used as a source of protein in smoothies, and any number of desserts. Or, lightly sweetened and served as is (as is commonly done in Japan).
I *am* sure that leftovers are nowhere near as tasty.
No, you aren't, you are assuming. Considering I just named several dishes that I'm pretty sure you had no idea even existed, you have no idea whatsoever those leftovers would taste like. Now, i'll be subjective too - chicken in the US is pretty darn terrible. In general, it tastes like cardboard (and this is by design - flavor takes time to develop, and when birds need to be slaughtered by 6 weeks that just doesn't happen). Go to France and try poulet de bresse and realize how truly abhorrent American chicken really is. It's not worth the animal suffering that goes into it.
Unless you live in a place where meat is very scarce, you only eat filet or ribeye every night, or insist on grass fed free range low stress hand massaged beef the financial impact of meat vs no meat is very minimal.
is seemingly unfounded. Unless you consider a 50% reduction in cost to be minimal, which I do not. Interestingly, the cost of 39 weeks of tofu ($139.23) is nearly a wash with the cost of only 13 weeks of chicken ($136.50). If someone is culinarily inclined, there are even cheaper options. Indian foods, beans, whole grains, etc.