Today, Bitcoin mining is increasingly dominated by large mining farms, industrial operations, and investors with massive budgets. Small miners and hobby miners are becoming less common every year.
Exactly as planned and predicted by Satoshi:
The current system where every user is a network node is not the intended configuration for large scale. That would be like every Usenet user runs their own NNTP server. The design supports letting users just be users. The more burden it is to run a node, the fewer nodes there will be. Those few nodes will be big server farms. The rest will be client nodes that only do transactions and don't generate.
Which means, that even if it will be technically possible to mine at home, and earn a few satoshis from doing that, then still: it won't be profitable. Buying the same amount will be cheaper for a typical user, than mining that amount.
Also, if you want to lock coins on Proof of Work alone, then you actually can. For example:
https://bitcointalk.org/index.php?topic=5551080.0Which means, that you can
increase the reward by attaching more coins for example to
bc1qn9vp8l5rs7huyl237s4q9lhrzcs0mzaajt528ysq3wgnzvlkay5sdfz6am, and then, any miner, who will check around 2^64 double SHA-256 hashes, would be able to move these coins anywhere. And guess what: it is currently more profitable to try mining the next block, than try to claim 53,000 satoshis from such address, if you calculate the needed hashrate per satoshi. Maybe if that reward will be bumped, without making the challenge harder, then some miner may try to collect it, while also confirming your transaction.
So, technically, as a user, you can always lock your coins on such scripts, and then, making a double-spend will be as hard, as re-mining the puzzle for a given address. Then, if you create any standard transaction, and one of your outputs will be used as a CPFP, along with the puzzle, then some miner may solve the puzzle, while also confirming your transaction. This is how sidechains can be built in a trustless way today, without BIP-300 or BIP-301 on Bitcoin. Then, they don't use Merged Mining, but they can use Proof of Work from the puzzle, and they can use real BTCs, without creating new altcoins out of thin air.
Which means, that if you want a decentralized solution, then I just described it, and you can use it, if you want. But in practice, for years, people did it differently: they just released altcoins, which were easier to mine, and then they simply sold them for BTCs. This is probably the fastest way to "mine" some satoshis, if you need to get them in that way: by mining some altcoins, and simply selling them. My idea doesn't change that model that much, it only makes it possible to do on real BTCs instead. And putting real satoshis into such puzzles is not that much different, than buying altcoins. Because for you, to sell a given altcoin for BTCs, some other user have to put some BTCs into it, to make ends meet, and form a transaction between a buyer, and a seller.
