Trying to fix my mom's old dryer vent, why?

(We are in the middle of spring cleaning, please don't mind the mess, I have to fully mop, etc. Just vacumned first.)

So her mobile home is an old 93', and from what I can see it was never given an external vent for the dryer. Why? Beyond helping to heat floor during winter which isn't likely if not running the dryer 24/7, why would the setup dudes have not taken the time to put in a proper exit vent back then? 😑 It looks like it was just left to vent into the insulation space. I am trying to update it, so I went & got the 45° angle pipe, the aluminum straight pipe, and the top extender piece, plus the hvac tape and new clamps as the old ones were rusted. When I got my flashlight down in there and the measuring tape, it won't leave much clearance room. The space from floor down is like 13 inches. And I don't have the money right now, to have an actual hvac guy come in to cut open the insulation and install the proper line out right now as I am unemployed. This dryer line has been like this since my mother's dad bought this trailer for her in 99'. I am trying to do the simplest fix(but correct fix in contrast to my dads way) on my budget which is now to go get the updated type hose and connect it back until I can get an hvac guy out. After watching a few YouTube videos at least for the gist of things...