Monero is a different league to bloat. We are talking 100+gb in a very short timeframe. Long term 5+ years even worse
And web wallets etc promotes centralization. Everyone will depend on a minor few for the blockchain. DDoS it and watch the coin die.
The Monero bloat is fine for now when you have like 100 users. For mainstream, the cryptonote tech isn't anywhere close to being a viable solution.
You're conflating - web wallets do not promote centralisation in and of themselves. Satoshi even theorised that there would be a reduction in the number of full nodes, and for convenience sake SPV would become more popular. At any rate, even if there were only a few non-mining full nodes it would largely be irrelevant - centralisation is only a concern on the mining side, hence the 51% pool problem that has plagued Bitcoin.
I'm quite unsure as to why you're talking about "mainstream". We have alpha-level software that requires some comfort with the command line to operate. We keep saying this, but everyone keeps talking about "adoption" and "mainstream use". We're solving fundamental, extremely low-level problems, and well after they are solved we can consider "adoption" and "mainstream use".
Thankfully, Bitcoin is also pretty impossible for "mainstream" use, so it's probably a good idea to either clearly define "mainstream" or get off the merry-go-round.
At any rate, let me make this as clear as mud to everyone: Monero is far from ready for general consumption. We don't need to be reminded of that, since we're the ones saying it! Of course, usability is a long-term goal, and finding a solution to "bloat" (such as it is) falls squarely in the "usability" camp.