Yes, because an electric parking meter uses only a few watts of electricity and may not even be connected to the grid (the most common ones I've seen just have a tiny solar panel). A electric vehicle charger may use 200 kW and require its own dedicated transformer. A fast charger is a fairly substantial cabinet. Now you're jackhammering the sidewalk to bring an underground electrical service to that spot.
Can you apply your thinking to petrol stations. We build floating city's to extract oil thousands of meters down. Is running some cables harder then that?
An off shore oil well will basically extract black gold, paying for themselves in no time(at least when the oil barrel price was high). Electrical charging station on the sidewalk not so much.
The current needed to charge an EV is far higher than what a parking meter was wired for.
Privately run charging stations on public sidewalks are few and pricey and most of the time sitting empty.
So it's clear that if you want a mass switch to EVs the government will need to subsidize the infrastructure to make EV charging affordable. However, digging up the sidewalks of a whole city with public funds to cable it for EV charging is the last thing taxpayers want to hear even in green Austria since it's seen as a something that will only benefit the top % that can afford EVs and they already have charging stations at their houses.
I imagine the wiring to the meters is designed to carry the current necessary to run an electric parking meter and wouldn't hold up to the current required to charge an EV.
We already have similar on-street charging stations like that in Berlin, just not enough. I suspect the reason it's not all street-parking is the strain on the electric infrastructure which would probably require a lot of rewiring.