We can have both. If everyone has more disposable income as they would under a PC government, than that's more people having more to spend.
I understand that less taxes theoretically = more disposable income (though the "theoretically" is key, because while I as the average taxpayer may have more income in my pocket, I may now have additional expenses because of the programs lost to the tax cuts - maybe my health care costs go up, maybe my transit/commute costs go up, etc.). But - putting aside the issue of whether my disposable income actually goes up or down - more disposable income and (possible) improvements in the economy that flow from this
does not mean that suddenly more transit will be built, more teachers will be hired, more nurses will be hired, or more affordable housing will be built simply because the economy is booming. All of those things come from the government. No individual is going to say "I have so much disposable income now, I'm going to spend it on building a subway and hire a new teacher at my kid's school!" No, instead their money will go towards the banks (via their mortgage) or a corporation (via groceries and gadgets). So you're comparing apples to oranges: disposable income and taxes are spent on different things.
So really, the debate isn't
"tax increases" vs. "tax cuts". It's
"teachers, transit, nurses for all" vs. "a couple fancy dinners and the latest iPhone for all". The debate is about what you view as more important for yourself and for everyone else.
Also, what I actually like about taxes is my money is essentially being leveraged (probably the wrong word, but you'll get what I mean). If my taxes go down by $200/year then I and everyone else get $200 in disposable income and we can each spend that on a couple nice dinners in the city for ourselves. But if my taxes go up by $200/year,
everyone else's go up by $200/year as well. Given there's 13.5 million people in Ontario that means there's now
2.7 billion/year to be spent on things like transit, health care, and education. My agreeing to (i.e. voting for) a $200 increase has essentially been leveraged by me to allow for 2.7 billion of new things - things that will probably impact my, my friends', and my family's quality of life far more than those two nice dinners were going to.
(Disclaimer: yes, it's an oversimplification to say that everyone in the province would pay the same tax increase. And yes, the example presumes that I was in a decent enough position that I didn't immediately need that $200 to survive.)