You're quite right. Just as some rough math, Love Park is 2 acres and had a budget of ~$15 million. NPS is 12 acres so, all else being equal, that'd be $90 million (so approx. $100 million, just as you said).
No parking garage under Love Park though, and in truth, we VE'd Love Park in a few ways. We lessened the quality of pathway paving, we decided the pond didn't need to be year round or convertible for skating, we didn't provide public washrooms either.
Love Park is still a very good thing, Claude chose carefully where to VE, where possible, picking things that could be added-on or fixed later (washrooms, upgraded paving). Still, the 'dream' version of Love Park was likely closer to 25M
You're absolutely right in everything you said, but I can't help myself from dreaming! I'd like to think we are still capable of big, exciting city-building...
First, keep on dreaming. Nothing every changes with a shrug, and a "It'll have to do".
That said, regrettably, University Park is not on at the moment. That's even though a donor came forward to pay for some of the planning/EA costs for a portion, and U of T was willing to contribute millions. I can't speak to all the details, but some mixture of complexity of issues along with the true bill of doing even one segment completely just stalled it. It may come back, one day........but barring 200M or more falling from the sky...........not anytime soon.
Now.... I will tell you there are some potential big public realm projects, beyond the ones we know about that are moving too slowly for anyone's liking (John St, Downtown Yonge, Yonge - North York etc.).
But I can't get out in front of anybody's press releases, especially when there are details to iron out..... Hold out hope, demand better, but pick your battles too.