OK fine, but just because I quite enjoy arguing with techbros. I'll do it with sources and everything.
99.9% of all species that ever existed are extinct. https://www.amnh.org/exhibitions/dinosaurs-ancient-fossils/extinction/mass-extinction
Humans are like all other animals. Eventually we will go extinct. Trying to avoid that on a population level is as fruitless as trying to avoid death on an individual level, and in my opinion (this is the non scientific bit) just as narcissistic.
So that's why the first para is pointless, before you even get to whether humans could viable survive on Mars.
Here's some info about Apollo (for readers, not you, you know this already)
https://www.quora.com/How-much-fuel-does-it-take-to-launch-a-rocket-into-orbit-How-long-would-that-fuel-last-if-the-rocket-remained-in-orbit?top_ans=1477743684300655
203,000 gallons of kerosene and 318,000 gallons of liquid oxygen. This is approx. 6, 896, 316, 116, 393.501 calories according to this (https://www.convertunits.com/from/gallon+[U.S.]+of+kerosene/to/calories#google_vignette)
1 gramme of wood contains 4 calories of energy. So this is approx 2,240,790,291 kg wood.
According to Quora the average weight of a tree is 1000 to 6000 kg (https://www.quora.com/How-much-does-a-tree-weigh#:~:text=The%20mass%20(not%20the%20weight,tons%2C%201000%E2%80%936000%20kg.) Let's take 3500kg for this.
The equivalent energy to the kerosene needed to launch apollo is 640,225 trees.
Assuming this as a guide you need 1100 to 2500 trees per hectare.
https://defrafarming.blog.gov.uk/sustainable-farming-incentive-pilot-guidance-plant-trees-to-extend-existing-woodland/
Taking the middle for the calculation again, the amount of trees needed to provide the energy would need 356 hectares, or 3.5km sq of trees.
For reference, the US have estimated the average person uses 640lb (290kg) of wood per year. America is a high user of resources so this is generous.
https://apps.fs.usda.gov/forest-atlas/benefits-wood-products.html#:~:text=With%20more%20than%20313%20million,each%20side%2C%20every%20single%20day.
The energy needed to launch apollo is equivalent to the wood needed for 7.7 million Americans.
3.5 km2 of trees/ wood for 7.7 million people seems quite resource intensive therefore I also think your second para is not accurate.
Having cheap space flight enables a staggering amount of human advancement that you just don't get any other way.
Having cheaper space flight might enable human advancement you don't get any other way is a more realistic way of putting it. Assuming we don't all die from climate change before those benefits are theoretically realised.
This para is your opinion. It's OK for people to disagree. Even if they are "low T"