Culturally though it has a greatly diminished role. If I remember correctly, during the last European election the largest parties spent about 500k on social media ads. We're still overwhelmingly dominated by traditional media. Angela Merkel has no social media presence, and if I had to guess even the most popular politicians maybe have a few ten or maybe a hundred thousand followers on Twitter.
Someone running for parliament in the UK, for example, is allowed to spend about $0.26 per voter † in an average constituency (of 72200 voters).
It's certainly not a perfect system, but it does mean if you earn £100k it's very easy to become an MP's largest donor.
† (The rules are more complicated than that, of course - there's separate spending by the national party, one free mailing by the royal mail, rules for tracking the equivalent value of volunteered professional services, and so on...)
There are no limits on donations, for example. Anything below €10,000 does not even have to be reported. And reporting only happens once per year.
Also the parties are significantly publicly financed and the amount of money is much lower, due to the much shorter campaign span, making the process much more egalitarian. For example the largest party in Germany, the CDU/CSU spent 30 million for the entire 2017 general election campaign (about 30-40% of the vote generally), and the smallest parties spend a few million with about 5% of the vote. So not much difference.
I'm completely shocked when I see US candidates in primaries spend tens of millions, or individual senators.