How to improve the degreasing process? My Situation :
I degrease my drive train occasionally and absolutely hate the job. I also maintain my dad's bike, so this whole degreasing thing is really getting on my nerves now.
I use solvents such as paint thinners, petrol etc rather than what is typically marketed as 'bicycle degreaser', considering that to be weaker product for much more money.
[Typically in my region, especially marketed degreaser costs about 27x more than petrol by volume (if lucky), not to mention being generally less effective as far as chemistry is concerned]
Also, I use toothbrushes instead of a chain cleaner tool, but am realising that those devices are a good and reasonable investment if I am to do this regularly.
Not to mention I get pretty OCD about clean drivetrains but can't take the bike apart, because I have neither the tools, nor the time nor the patience to assemble and disassemble the drivetrain.

The Problem(s) :
Despite being excellent solvents, they aren't appearing to great cleaners.
If I intended to submerge my cassette and chain in them, sure they'd be perfect. But I intend to apply, brush and rinse.
For this task , these are quite the pain in the arse, requiring lots of re-application due to having vaporised quickly while I got up to stretch my back or sip some water; requiring more scrubbing to no end; and with petrol , being quite difficult to rinse off.
In the end , I get a decently cleaned but not sparkling chain and cassette , a through 2 hour back-straining workout and absolutely no desire to go clean my dad's bike .
Sure, the evaporation and chain-scrubbing issues can be fixed simply by using a chain cleaner tool. The rinsing problem can be used by boycotting petrol and sticking to thinner.
But of course, the cleaning of the cassette remains unsolved - it still takes way more brushing and odd angles than tolerable.

The Fantasy :
Now, a couple days back I saw a YouTube ad for WD40's bike degreaser. I understand ads are hyperbole and inaccurate. I also understand that regularly buying specially marked bike degreaser is outside the bounds of my budget.
BUT , the ad showed the dream degreaser. All you had to do was backpedal the suspended bike a few turns while spraying degreaser from the can to the cassette. The shit would foam up like luxurious soap. You waited for a while. You rinsed it off with a garden hose. Ta-Da ! Sparkling drivetrain !

The Question :
To someone who has actually used a marketed degreaser on his drivetrain, is the foaming and ease of rinsing real ? Does it actually get the grime very well with minimal brushing , like they show in all the internet tutorials ? Or is this just the magic of the exaggeration of an ad, and the jumpcuts of GCN and GMBN ?
Do I really need to invest in any more than a Chain cleaning tool ?
I don't know why you think bicycle degreaser products are 'weaker for more money' when you have basically proved to yourself that gasoline (petrol) is a very poor cleaner because it evaporates very quickly.
I've had success with a basic citrus degreaser available at Home Depot that costs $4 for a reasonably sized bottle. It's effective at loosening dirty chain lube, minimal brishing of the chain and cassette is required and it rinses off with water taking the dirt with it.
I should point out that you are likely over-cleaning your chain. Too much solvent/degreaser removes the lubricant from deep between the link plates and rollers. I've found I get much better chain life by only wiping down the outside of the chain with minimal degreaser.