I have read that varicaps (capacity diodes) are a "modern" alternative to variable capacitors. In several electronics books only positive properties of varicaps are mentioned.
But several major distributors (here in Germany) simply don't offer varicaps, or just have less than 5 of SOT-23 models. (For comparison: same distributor offers around 1000 different diode models.)
At three largest German distributors of electronic components I couldn't find a single DO-xxx case varicap. Only SOT-xxx.
Does it mean that varicaps are obsolete? If so, what do people use in today's circuits as "replacement"? Or, more general, is there some more common "concept" to vary capacity?