If you want your electrum wallet to be completely secure, you should create it on an airgapped device.
This means that you should use a device which has been always offline and will never connect to the internet.

Yes. This is a good advice. But, I don't know how people use their computer or mobile device without an internet connection. If you can afford to buy a laptop or a computer to use as a hardware wallet and never connect it to the internet, you should be able to buy a hardware wallet as well. Simply disconnecting and never connecting it to the internet is not enough.

You should not connect any device to it that has internet access, and you should not use any pen drive to transfer data. Because you never know if there is ransomware or not. A hardware wallet costs around $50 to $200 depending on the model and the company. You should take one if you are serious investor.

That's one way to do it but you need to make sure you're creating the wallet on an air-gapped device running secure open-source software. Which, probably majority of the masses aren't capable of doing so they're better off just buying a cheap hardware wallet.

Also, the limitation of that is it's solely for hodling. If you want to use the bitcoin to pay for something, you're putting your funds at risk for connecting to the internet.

No it's not.
I have seen to many people making mistakes with their imagined fake airgapped system, that I can recommend everyone to stay away from setup like this.
There are to many things that can go wrong, and people don't really understand how to keep everything offline and updated in the same time.
It's not that hard to get hardware wallet today, for example Satochip cards are lees that $25 with discount, Safepal is almost free, Jade and Trezor One are aroud $60, etc.
If you don't want buy anything, than using old smartphone would be acceptable with disabled all connections (airplane mode) and removed sim cards.

No.
You don't have to complicate things with hardware wallets, just make a transaction.
If there was no internet, there would be no bitcoin, so internet can't be the culprit or enemy of anything.

As others have said, this kind of setup will fall under the category of air-gap PC and it should not be connected to the internet once you have set up everything. Although if I will have to choose between a hardware wallet vs a air gap pc, I will go with the hardware wallet.

And if the person that known have this kind of setup since 2013, then good for him. He could be very knowledgeable and knows how to protect hit Bitcoin with that kind of setup. The key here is that you know what you are doing if you chooses air gap setup.

But hardware wallets are not too expensive, many wallets are quite cheap, such as the Trezor One hardware wallet, which costs less than 60 USD each. And I think if we are serious about our bitcoin investments and intend to keep them for many years, spending $60 to own a hardware wallet is not too expensive. But it's okay if we use Electrum wallet or any open source software, as long as we meet enough factors to be safe for it. You can use any wallet you like, but don't make the excuse that a hardware wallet is too expensive to own.

Doesn't it look strange when a person can afford to invest in cryptocurrencies, but can't afford a hardware wallet for ~$100 (often even less)?

Why all this complexity and twisting, when it’s easier and safer with a hardware wallet?

One day there will come a time when you will have to connect to the Internet to sell crypto assets, and at this point a catch may await you with a compromised PC (infected with a malicious program).

Shouldn't we be careful about this?

Isn't the user himself the enemy of his wallet? By not recognizing hardware wallet, users make mistakes in storing crypto assets, leading to losses with cryptocurrencies. So far, nothing safer than hardware wallets has been created against online threats (taking into account that the hardware wallet is from a reliable manufacturer).

As long as you can make sure the device isn't online as long as you don't need it, I think it's still safe to use an electrum wallet to store Bitcoin as long as you don't spend it.
Hardware wallets are also inexpensive to purchase if one has the desire to own one.
The safest way to use a Bitcoin wallet like Electrum can be followed by the method given by people here.
Regarding wallets storing Bitcoin, don't take it lightly if you don't want to regret it.

No, the practice is not similar to using a hardware wallet. On hardware wallet you're putting your trust the wallet creator to create something genuine and safe for long term of your crypto and this is why open source hardware wallet is advise for public flaws checkup.
The practice you explained is called airgap wallet and it's secure if used a device that's not physical, or wireless connect to the internet and other computering devices.

Yes no doubt you have given a good advice. Your advice is reasonable and accurate.

But if you are a high level investor then you directly buy hardware wallet and deposit your BTC in that wallet. Only use that hardware wallet later when you are ready to sell.

On the other hand, caution should be taken for added security when using Electrum wallet. Create Electrum wallet using internet connection only once by electronic device i.e. computer, mobile or smartphone and it is better not to establish internet connection on that device before preparing to sell BTC. In this case, do not use any type of input device to protect yourself from harmful viruses like malware or ransomware.

In my personal opinion, it is better not to use Electrum wallet. In this case you should get used to using hardware wallet.