i seriously doubt that that is the reason. as others already pointed out the usage is a lot more than what you think but even if it wasn't that shouldn't be the reason for not supporting Bech32 addresses. their platform already recognizes the addresses and decodes the output script into a correct format. heck it even has a bech32_encoder that it can encode the
Sorry to bump this, however, it is odd they haven't configured them yet. Surely the longer they leave it the more time it'll take to go back and change it later?
And it's not like bech32 are going away any time soon either...
as far as the code is concerned it is one change and it doesn't matter when they do it, it will be the same amount of time.
as far as their database is concerned you may be right since indexing is involved as a block explorer. but i may be wrong since as i said their system already understands these types of addresses and it understands the new SegWit transaction format with witnesses.
anyways, who cares. we should seriously stop using blockchain.info they haven't even upgraded to patch the recent vulnerability. somebody exploited this on TestNet and they easily considered that block as valid and have it on their block explorer!