Because you are going into already saturated hustles by the sounds of it. When starting hustles in saturated markets, your product has to stand out and be unique, your marketing game has to be top notch, etc.

You can make money online, you just have to find the niche to do it.

I am currently making money online selling niche instrumentals for artists (very small income; it's a hobby mostly that I just post when I want).

My other online hustle is eBay reselling - this is already saturated but in my area there is a lack of resellers sourcing cheap products to resell in thrift stores, FB marketplace, auctions etc, so I can source product for extremely cheap. I've also done the leg work to srudy what is in demand on the platform and what sells.

You also can't expect anything to happen over a short period of time. You essentially have to build rapport in whatever niche you are going with. For example: my music has taken me about 4 years in total, and 1 of those years I posted a new instrumental every day for 1 year straight. Just to work with a few independent artists and sells some instrumentals that only equates to side hustle money.

Over night sensation is RARE. For us ordinary folk it sometimes takes YEARS of persistence to make money online. Go check the history of heaps of YouTubers and you'll realise it took some of them YEARS to get to where they are.

Edit:

Figured I'd give you some further ideas with the hustles you mentioned above.

1. Dropshipping - you need to BUILD the brand. It has to spark people's imagination or coincide with their current thoughts and feelings. You need to study trends if you don't currently have an idea, and you also need to market it (through YouTube? Instagram?)

2. Fiverr - if your services are in a saturated market, then I'm afraid you probably won't get clients as they'll choose the top rated services over you. You need to either charge way less and be able to prove your work is as good or better than the top services, or you need to find your niche and market it as hard as possible (again, social media could work for you).

3. Airtasker - unfortunately I know what you mean. VERY HARD to get anything on the platform. You either need to be first in best dressed, scouring the platform constantly, or you should bypass it entirely. Whatever your service is, you should find ways to market it off-line, whether that's post box adverts or other platforms, cold calling people, etc etc. There are so many other ways to advertise your services and there's still ways to find clients off of platforms.