> I am not sure what author is trying to hint. But solar does not need artificial subsidies, and can pay for itself!

I think he is describing a subside that some governments gave years ago: you installed for example 5K, and get paid for whatever they generate at 300% market price, for a long time (25 years?). Today you find out that upgrading panels would made perfect financial sense, if you were selling at 100% and are going to sell electricity at 100% (you will be doubling the output for a tenth of the inversion 15 years ago), but as the subsides of 300% no longer exist, you will be actually losing money by upgrading.

That's not true. You can upgrade to the same capacity on the previous feed-in tariff and keep what you had. It makes sense to upgrade as you can then fill the extra space with additional panels (which will not be on the old tariff, but can be a separate system).