Replicator 2 nightmare

Hello,
I've had a Makerbot Replicator 2 since roughly around 2013. Since then I have been able to successfully print....maybe 50 at the most things successfully. This thing has been junk since I got it. I don't claim to know a lot about 3D printing but i have done a lot of reading about the problems I'm having...which are many. I fix one thing, I get a good print and then I can't get it working again for months. Try something else and then its good again....then fails with a problem previously thought fixed. I really just want to throw this thing out the window. But I want to gather opinions, maybe see what suggestions are out there first. My main issues are extrusion/clogging it seems. My latest issue is it won't extrude when starting the print job. If I go to "load" filament, it comes out fine. Then immediately start the print again...and nothing comes out like its plugged. Even though it was coming out beautifully during the "load" function. I successfully printed an object the night before. Trying to print the same thing with same settings and nothing. Here are some things I have done and questions I have.
Replaced the nozzle with a .4mm
Replaced the ceramic insulation/kapton on the heater block.
Disassembled the hot end and made sure everything was clean
Replaced the filament drive with an upgraded aluminum type
Tried different filament
Filament is not binding
Replaced thermocouple

Questions:
How important is the active cooling fan? The one that blows towards the bottom near the nozzle. My ducting broke a long time ago and I haven't replaced that...Not sure how much that would effect extrusion problems though.
I tried a .5 mm nozzle and it worked great with not plugging or stopping, however the print looked like crap. I can't find anywhere in makerbot desktop to change the nozzle size for the slicer. Any way to adjust settings for a bigger nozzle? I know resolution goes down a bit but thats alright as long as the thing actually works
The thermocouple i got is not an oem makerbot thermocouple. Could that be reading wrong and not getting the right temps? Or so far off it would cause this many issues? I just replaced that a few days ago though and these problems have been present for years before that.
I know they have a "smart extruder upgrade". With my serious lack of faith in makerbot and the seemingly piece of junk I have from them already, i'm hesitant to spend that kind of money if the thing is just going to continue being crap. Would I be better off just spending $300 on a cheap printer on amazon? Or other options around that price range....I'm not in the mind set to spend $3000 on another printer with the experience I've had with this thing.
If you were me, what would you do?
Lastly, I know this is a lot of information/venting/and questions. I apologize and I don't expect the perfect answer from any one person...I would like to just compile opinions and such. Thank you for your time with any suggestions anyone may have.

okay - first thing. throw makerbot desktop away and start using Flashprint from flashforge. Sooooo much better. Select flashforge pro. https://www.flashforge.com/download-center The print area duct is important - but you are right it shouldn't effect extrusion. Do you have the same problems with both extruders ? or just the one ? The smart extruder is not for a replicator 2 - and if you think you've had problems, go dig up the issues they had when the 'smart' extruder machines came out. It was almost as bad as the ender 3 ! Bed levelling is important, but again won't effect actual extrusion. Getting the filament to stick - I really recommend Dimafix. Just wipes on and holds stuff when hot and releases when cool. A little goes a long way and lasts a long time. Try using flashprint and if you are still having the same issues, maybe think about changing the motherboard. The mighty boards are great - but extrusion issues do crop up with them quite regularly (had similiar extrusion issues with my replicator clone after about 5 years of heavy use).

okay - first thing.
throw makerbot desktop away and start using Flashprint from flashforge.
Sooooo much better. Select flashforge pro.
https://www.flashforge.com/download-center

The print area duct is important - but you are right it shouldn't effect extrusion.

Do you have the same problems with both extruders ? or just the one ?

The smart extruder is not for a replicator 2 - and if you think you've had problems, go dig up the issues they had when the 'smart' extruder machines came out.
It was almost as bad as the ender 3 !

Bed levelling is important, but again won't effect actual extrusion.
Getting the filament to stick - I really recommend Dimafix. Just wipes on and holds stuff when hot and releases when cool.
A little goes a long way and lasts a long time.

Try using flashprint and if you are still having the same issues, maybe think about changing the motherboard.
The mighty boards are great - but extrusion issues do crop up with them quite regularly (had similiar issues with my replicator clone after about 5 years of heavy use).

Thanks for the information. I will definitely download flashforge and use that.
My printer did not come with dual extruders. I know it always was an option but I bought it with only one.
Yeah I saw how horrible the smart extruders were after posting this. Glad I didn't make that mistake, even if it was not for my machine.
Not to sound naive or anything but how does the mother board effect the extrusion? Not saying you're wrong, just curious of the variables that go into it. You definitely are more knowledgeable about this than I am.
Thanks again!

stepper motor controllers do get faulty. Also over time even printed circuits can wear out.
Plus the only thing on the mightyboards that are actively cooled are the stepper motor driver chips.
Is the cooling fan still running ?

The stepper motors themselves almost never break.
You could try a new motor, but the odds are that's not the problem.