Can Decentralized Marketplaces be real alternatives to Alibaba, Amazon, eBay?

(picture source)

So far there are no so much (or any at all) who has succeeded in that. Although many have tried. For example: BitBay (BAY), Syscoin, Soma (SCT), CanYa (CAN coin), Dmarket (DMT), Substratum (SUB), Nxt (token), RSK (BTC pegged), Parity (several crypto), BlackHalo (BTC or BLK), Phore (PHR) etc. - to name just a few after a brief research. There are some new emerging as well (see more).  

There is also P2P based OpenBazaar, which doesn't have nor use any of its own crypto coin as those others, yet at the same time provides the opportunity to pay in several Crypto (main are: BTC, BCH and Zec; other Cryptos can be used for payments too, but through Shapeshift). Since July 2018 OB (version 2.2.2) also provides Trading facility of over 1500 Cryptos as a digital asset or kind of virtual product in other words, as any other merchandise, albeit intangible (i.e. non-physical). However it looks like it is the biggest (perhaps even the only) Decentralized Marketplace which facilitates the trade (shopping / selling) of tangible (physical) goods.

Here is an example of one such stores (widget here), ran by one of my friends. (please browse it and perhaps choose something for yourself, to support aspired fellow Crypto user who tries to earn something online to get enough Steem to start own Steemit blog :) )

After some comparison what I have found is that all such DMs have few common flaws, comparing to the traditional (mainstream) auction and marketplaces, such as:

1. they are mostly not easily visible on internet and therefore found through search engines (well, some as OB, has created for that web version of their blockchain network), which makes it difficult to promote or advertise online to wide auditory;
   
2. there is no yet such thing as "blockchain-internet" (or B-web, or whatever you prefer to call it), an alternative to existing WWW, this each of DMs is sort of "isolated" from each other: in other words not connected with other similar networks (although there are already some efforts to rectify this issue, for example Parity's project PolkaDot which aimed at connecting various blockchains through "multi‑chain technology") - that also adds to difficulty to advertise / promote (as on standard internet);
   
3. accordingly there are no yet "blockchain search engines", unified explorers and therefore advertising service providers (as on standard WWW);
   
4. there are no yet payment gateways convenient for any and every blockchain network (although some attempts are made as Shapeshift);
   
5. finally, there are no easy and convenient "fiat-crypto" bridges (gateways) which would be really Decentralized and hassle-free (without KYC and all such stuff), reliable, user-friendly, etc.

Perhaps there are few other flaws which I have missed above (may add some later; would appreciate if others add in comments). But even these above mentioned, IMO make it quite not so easy to use successfully enough and especially to make them as an effective TRUE alternatives to such giants as Alibaba, Amazon, eBay, Etsy and all such. Although the demand for alternatives certainly exists and would be fair to say it is quite high enough and where there is a demand - inevitably would be a supply! Sooner or later some would figure out how to address all those flaws and resolve them.

So far though, at present moment as I can see it myself (and as my friend told me too) - on OpenBazaar many stores do not have much sales (or at all) - that's the reality. In other words, to me that means: using Crypto as payment to buy actual goods (both physical and virtual, tangible / intangible) is still not widely popular. That makes me doubt that such DMs may survive for long at all - what to speak of becoming competitors for those mainstream giants.

Which in turn leads to next conclusion: without finding the ways of using Cryptocurrencies widely for broad masses of population - how they would be capable of staying afloat for long?
 
Please share your opinions and thoughts in comments! Thanks for reading.