That's because Electrum doesn't recognize P2PK (Pay-to-public-key) outputs, and the first Bitcoin client paid that way when a node solved a block, or when one node paid another via TCP/IP. Eventually, Pay-to-IP was phased out, and miners used other mining software which used P2PKH (Pay-to-public-key-hash).
I had the same question about a year and a half ago:
https://bitcointalksearch.org/topic/electrum-doesnt-show-rewarded-coins-5327269wrong
1. bitcoin core, other wallets and miners do understand P2PK because they do show p2pk transactions.. only electrum does not. meaning the fault lays within electrum.
(dont play your agenda game of pretending bitcoin is broke but your favoured service is good, especially when your favoured service is the thing that is broke!)
lets sidestep into blackhatcoiners offtopic/meader and misunderstanding of the p2ip which is not even something the topic creator mentioned. but because blackhat did and said many mistakes, needs to be rectified for other readers sake
2. pay to IP was not about some special way to confirm transactions outside of usual mining rules
pay-to-ip was a way to just send a unconfirmed unbroadcast signed TX to another user directly instead of the whole network seeing it (pre-confirm via peer-to-peer relaying to everyone. )
it was a privacy thing. of not annoucing a TX until its in a block by not letting everyone have a copy before the block its confirmed in..
this would mean the recipient got a unbroadcast/unconfirmed signed tx, which he can then broadcast to everyon tolet then put it in thieir block..when he wants to get it confirmed
or solo mining it where people only get to see it when the recipient or sender included it their own block they solved, as they were the only ones with it pre-confirm.
back in the old days there was 'no pools' it was solo mining.
pay-to-ip was not about paying in an immutable/confirmed way to someone in a different method other than the block solving method that existed at the time(solo) was more about giving it to only to a select few people(privacy) so that not everyone seen the signed tx before it appeared ni a blcok, and if those people included it in their block attempts and their blocks confirmed, then that transaction is confirmed and finally seen by the network for the first time,
(you should know this very well with your offchain favoured system (of the privacy aspect of the bitcoin network not seeing it until close session broadcast) it has nothing to do with deeming the other person as confirmed immutably paid by pretending the unconfirmed payment is a final settlement(which foolishly LN tries to infer.. which is where you are mistaken, but should have learned by now))
3. when most blocks became solved by pools and not solo. the usefulness of pay to ip became useless, because the chances of someone then solo mining to include the TX (to get paid) became less. thus people had to broadcast to the network publicly for the chance for it to get into a block
anyways... back to talking about the P2pk:
4. pools even now can still accept and collate into blocks p2pk transactions. mining (hashing blocks) didnt change due to the creation of newer tx formats
now that has been clarified
the reason electrum does not show p2pk.. is not due to pools. its not due to mining.. its due to electrum. and only electrum not being coded well
as admitted by blackhatcoiner in his post he made ages before. other software does show the 50btc coinbase rewards. yep core, blockexplorer, blockhain.info, and so many more software do show it.. so electrum not showing it is a flaw of electrum
