We all can attest to the fact that there is no escaping from online advertisement as long as you use the internet. Ads keep popping in on Facebook, WhatsApp, instagram, blogs even sites like Nairaland is not left out. But the question is do people actually patronize these online businesses?
Let's look at the stats. Less than 200,000 Nigerians had patronize online businesses, note this number don't necessarily patronize on a daily bases. Considering the number less than 10% of Nigerian had patronize businesses online, this number is relatively small compared to U.S.A which over 69% of their population had patronize online business.
25% buys things online atleast once and 47% of online patronage is from Amazon. No wonder Bezos is the world richest entity.
Enough with America let's talk Nigeria. Why is the patronage very low here in Nigeria? What are online businesses not doing right. I will highlight a few. They are as follows

insanely high cost product sold being sold
We all can attest to this. Most online product or goods sold in Nigeria have insanely high cost. Actually with this alone kills the need of selling things online. Online goods are relatively cheaper compared to the traditional store in other part of the world. Why will anyone patronize online businesses when he can easily get same product or good cheaper at a convenient store?
Like someone selling perfume oil of 15,000 naira when that same quality can be bought for 5000 naira in any mini mart.

selling perishable good online in bit
It isn't a taboo to sell perishable goods online, but selling in bit is pointless. For example a seller advertise his crayfish product online selling for #1000 while deliver fee is #1000 to be sincere why will anyone in their right senses patronize that when he can easily get it cheaper at a store. Even the delivery fee most times is almost equal to the actual selling prize.
If at all this seller wants to sell crayfish online, it will be preferable to sell an entire bag of crayfish maybe worth 15k for a delivery fee of 1000 naira now that's justifiable. Sell in bulk not in unit for foodstuff.
3. No effective working system or app like an escrow
When things are advertised online, interested people always ask this second most frequent question which is "is it pay on delivery?" And the seller will reply "pay before delivery" and give a long list of people he/she had supplied with screenshot. Even as at that it discourage potential customers. Trust is a two way thing.

hiding price of your goods
This is the most annoying. Customers can relate to this. The most frequently asked question when a customer is interested in a goods online is "how much" and the most repulsive answer by a seller is "DM me for price". Sellers believe they do this to hide price from competitors. You don't hide price from competitors they can also DM and ask. Make your price visible for customers, in fact it will even help you to sieve out uninterested customer. Amazon do this you too do it.

selling the right product
You know the most patronize goods online is clothes, shoes and accessories. If you really want to make more cash sell goods or products that are not easily gotten in your local stores. This is what makes the clothing line one of a kind.
I buy supplement online because I can't find it in my local pharmacy store.

With this I hope this will help people patronize online businesses and also sellers to fix their wrongs when dealing with online businesses.

Lalasticlala help your fellow online marketers

To add to what the OP is saying, I have also discovered another reason why online businesses in Nigeria don't make. And this reason comes from the literacy level of the country.

You even forgot delivering the wrong item

or lots of scam i even think scam is the number one