Negative prices in summer are going to hamper investment in generation plant needed for winter. PV is great while the sun shines, and for a few hours afterwards, not so great when there's hardly any sun for months.

Extending out the time to profitability (equivalently, reducing ROI; because the plants are idle in summer) means many proposals for generation in winter won't rise above the hurdle rate of ROI and won't get built.

Some regulation might be necessary. Maybe it should be that an energy provider must commit to a guaranteed minimum power output that applies year-round (of course excepting well notified planned maintenance and small outages for equipment failure).

IOW, a provider uses PV (perhaps) as one of a portfolio of generation methods, whatever works cheapest for reliable supply year round in the particular circumstances of the provider and market.

Allowing point of use (rooftop) installs of PV will make seasonal demand on the grid peakier too.

People will say, all those EVs are a distributed energy source. For seasonal variations, they're not.